Those interested can check out my walkthrough of the map. A full set of saves is attached.

About the map

At the start, we have a clear respawn with plenty of free or nearly
free chests and gold piles. The density of neutral monsters is low. The enemy is far away, and reaching them seems like a very long process. Fortunately, the spell Portal is found in the guild of one of the home castles. However, the guard at the enemy castle is serious; therefore, it is necessary to combine rapid magic development with the accumulation of combat power.

About troops and magic

At the start, we have a decent army from the starting castle for clearing, plus growth on day 3. For the main battle, it was necessary to choose a tactic for destroying a significant stack of enemy dragons: a heap of troops from several home castles, dragons from the captured enemy castle, or a strike stack of peasants. The latter option was chosen, largely because I wanted to fight with these rarely used units. Magical support on the map consists of the spell Portal, and in battle, Berserk, Paralysis, and Bless helped. An excellent set, needless to say.

About heroes

On such a map, heroes are our everything, as they allow us to quickly collect
necessary resources and bring much-needed peasants. During the
walkthrough, heroes were purchased 19 times, 13 of which were knights. A sorceress (3 Knowledge) and a barbarian as a combatant were also necessary. In the other 4 cases, maximum starting movement was required, which presented some problems since there are 8 warlocks at the computer. The final battle was conducted by a level 4 hero. Maximum Attack parameter was required from him; Crag Hack was the only hero who received the first 3 upgrades in Attack.

About resources

The main problem is the absence of precious gems for the guild at the respawn and the distance to the corresponding mine. There are no problems with everything else.

Day 1

We buy Hector and Whisper. Kilburn and Hector each receive a gargoyle and
run for money.
Hector takes 4 gold piles +600, +1000, +1000, +600 and runs up.
Kilburn picks up 2 piles +500, +1000 and a chest +2000.
Whisper clears the peasants, campfire +6 mercury, +600, breaks through the spearmen
with an army of 17 archers, 5 spearmen, 4 swordsmen, 1 peasant, 6
centaurs, loses a peasant and centaurs, takes a chest diagonally
down.
We buy Karlawn (the only one without dwarves), who on a fairy picks up
the freed campfire +6 sand, +600 and a chest +1500.
Build a castle (we will conditionally call it the second).
In the 2nd castle, we buy Tsabu (the only one without orcs), who runs
northeast and takes a chest +2000.
There we also buy Ambrosia, who on a goblin follows the path to the
neutral village.
Maximus arrives last and with a goblin stands before the orcs.
Result of the day: 2 castles and 7 heroes. Well, not bad.

Day 2

Maximus takes a chest +1000; now there is money for another hero.
Gallanta is bought out and with an army of 130 peasants, 11 archers, 22
goblins joins 15 orcs.
Maximus carries the orcs to Ambrosia, who captures the village.
Whisper joins 31 thieves, picks up a campfire +6 crystals, +600 and a chest +2000.
Hector grabs a chest +2000 and 14 stone near the 2nd castle.
Karlawn runs east; there a chest +2000 and the path to the stone
mine await her.
Kilburn takes a pile +700 and heads down for 3 piles with +15, +12, 16
wood.
Tsabu takes 2 chests of +1500 each and freezes near the third.
Now there is everything necessary to plant the 3rd castle, in which we buy Arturius (after first firing Gallanta) and a few archers.
Arturius takes the army from Ambrosia and with 17 archers and 15 orcs runs northwest for an artifact, picking up a chest +2000.
Build riders in the first castle.
Ambrosius with a goblin heads to the precious gems mine.
Result: 8 heroes and 3 castles; now we can act across the entire respawn.

Day 3

Generate peasant doubling in castle buildings.
Ambrosius continues his way to the mine.
Arturius hits archers, picks up an artifact +750 per day, a campfire +5
stone, +500 and a chest +1000, enters the dwelling. An army of
20 archers and 15 orcs is obtained.
Hector enters the 2nd castle and with 18 archers and a gargoyle hits dwarves,
takes an artifact +500 per day and a campfire +5 mercury, +500.
Tsabu picks up chests +1000, +2000 and +9 wood. (This is clearly not
optimal here, as first the hero will not fully use his move,
and then he will be short).
Whisper gives spearmen, swordsmen and thieves to Kilburn, who hits
gargoyles for a scroll +5 Knowledge and a chest. Then both run up, but in such a way
that Whisper is left with the gargoyle.
Maximus makes his way toward the compass.
Karlawn takes 16 stone and a chest 1500 near the sulfur mine.
Build a level 1 guild in the second castle.

Day 4

Kilburn hits dwarves, buys an artifact +1000 per day, takes a chest +1000.
Whisper takes the army from him and carries it to the first castle. Kilburn is fired.
Arturius runs to the 3rd castle.
In it we buy Tiro, 15 archers and 6 spearmen. Tiro takes
the troops from Arturius and passes them to Maximus. Arturius is fired.
Maximus with 215 peasants, 35 archers, 15 orcs, 6 spearmen
joins 14 swordsmen, but unfortunately, he is short one
move cell to take the compass.
Ambrosius takes a chest +1000 and the coveted mine.
Karlawn gets money from 2 chests +1000, +2000 and heads southwest.
Crag Hack (our hero!) appears. Having received troops and artifacts from Whisper,
he (after buying a book) with 8 riders breaks through spearmen, picks up a chest of 1000 experience (+1 Attack) and runs to the shrine with Berserk.
Whisper is fired.
Tsabu visits the statue and freezes before the minotaurs.
In the 2nd castle, Gallant is bought, who takes archers from Hector.
Hector grabs a chest +2000 and stops near the cemetery.
Build a level 2 guild.

Day 5

Ambrosius takes chests +1500, +2000 and a shield +2 Defense, is fired.
Karlawn grabs a pile and a chest of +1000 each, runs up.
Maximus moves toward Tiro, who takes the army from him and brings it to the 3rd castle. In it Haart is bought out and passes the army (except orcs) from Tiro to Hector. Tiro and Haart are fired.
In the 1st castle we buy Kilburn. He passes the army (together with remaining
thieves for accelerating several heroes; generally in the walkthrough it is assumed by default that if a fast unit can be given to a hero without losses, it is done) to Crag, while picking up a campfire. Is fired.
Crag Hack learns Berserk, gives the army to Gallant and stands before the second
castle.
Gallant carries fighters to Hector, but keeps peasants for himself.
Hector himself first gives them along with the compass that arrived through third parties to Tsabu, who hits minotaurs with an army of 88 archers, 18
spearmen, 24 swordsmen, 1 goblin, 8 riders (losing a goblin and
man-at-arms, sob-sob). Then Tsabu returns the army to Hector and on a gargoyle flies for gems, picking up a campfire along the way.
Whisper appears in the 2nd castle and with a gargoyle runs up, takes a campfire
+6 crystals, +600.
We buy Dimitri, who takes 9 stones and a chest +1500.
Build a level 3 guild.

Day 6

Karlawn takes 6 sand and is fired.
Tsabu reaches 2 piles of precious gems with 3 pieces each.
Maximus runs up for a chest +2000.
Hector passes the army to Gallanta, who via Whisper
(who managed to take an artifact morale +1) reaches the 2nd castle. Where
Tiro is bought and troops are delivered to Dimitri. Tiro is fired.
Dimitri breaks through swordsmen, grabs a campfire and artifact +2 Knowledge,
returns to the castle.
There we buy Ambrosia; he on a gargoyle enters the mill +2 precious gems.
Build a level 4 guild.
Gem appears, passes artifacts from Dimitri to Crag and on a gargoyle flies
down.
Crag (Knowledge 8) leaves in the 2nd castle 5 archers, 8 spearmen (+thieves), unbought peasants. With the rest of the army he jumps to Blackwind and captures it (+1 Attack). Spends the night there.
Whisper spends the night in the 2nd castle.

Day 7

Final chord.
All heroes at the respawn perform a simple operation as a result of which
Gem ends up with the remaining troops from all 3 castles, 5 huts and another 2 knights bought on the same day. Plus an artifact +1 Luck is delivered to her along the way after being defeated.
She delivers all this to Crag.
Crag Hack with a final army of 997 peasants, 105 archers, 24 spearmen,
23 swordsmen, 8 riders jumps in the direction of Alamar's castle. On
the way he meets enemy hero Castor and trades 20 archers for
the next level (+1 Attack), a sword +3 Attack and an axe +2 Attack.
As a final action, Crag Hack attacks Alamar's castle and captures it.

Victory.

Final result: 7 days, 12-4-1-9, 6 mercury.