So, I'm no veteran, but I have played a lot) In connection with the tournaments that have started on new templates

1. Common reasons for losing:

1.1. Templates that have ГО. Determine if it is possible to reach the castle from it in 1 turn, including with logistics. Keep in mind that a skilled player can often break through it (depending on the monster, of course), on a shield by the 5th week, but there are many of them to break through there. On a spider, Letose by the 6th. Game monsters, especially for Necros etc., can sometimes do it a week earlier. Accordingly, you need to be fully equipped by that time. That is, drag a chain behind you. And if it's possible to reach it in one turn, it is highly desirable to break through your own ГО and scout within those timeframes. Often the race being played will force one player to hurry, or that's just their playstyle (people of a particularly "jubilee" mold follow this). Usually we agree (or even in the rules) not to jump into the starting zone on such templates until all ГО are broken through. Sometimes you can skip breaking your own ГО and jump over it—to scout. Just in case) A chain is maintained so that the main hero passes troops to a left hero, crashes into neutrals, and buys back in the castle. The left heroes then bring the army along the chain in the same turn
1.2. Heavy losses often occur when jumping blindly through a double portal. You break through many minotaurs, but on the other side there are many water creatures... Of course, it's painful to lose units, but sometimes a sacrifice-scout with left heroes is used.
1.3. Moz overhauled the guards of various treasuries. I think it's in the change log. I often fear going in there for a long time) At least during the 1st-2nd week, well maybe into a crypt, but you can get beaten up there too). The Celestial Temple is a terrifying place overall; it's not comparable to Dragon Utopia)
1.4. On 3.0 without the mod, speed will certainly increase by a week due to OS, Path of War, stalkers, same-day portals for magic races, etc.
1.5. The difference between random and fixed is that, as a rule, it makes no sense to risk attacking neutrals. You'll find plenty of real ones without losing meat. Sometimes it's even better not to break through a portal with water creatures, but to wait.

ps. Sorry if these things are obvious to many)

Added after 1 hour 12 minutes
now briefly about the templates)

1. General. The mentioned timeframes can be significantly adjusted due to astral gates. When speaking of time, I am referring to the mod; on 3.0 it's often faster.
By "time," I mean a skilled player, but not a monster and not a novice. Monsters, rushers, or Necro specialists might be a week faster.
The templates were balanced by the creators for Hero difficulty. Resources, money, monster difficulty... Each template has a recommended size, but Moz seems to have already written about that.
In the description, I use the terms linear and non-linear. Linear is when you can understand where to go to reach the opponent based on the strength of portal guards or other distinguishing features, except for ГО, which is always obvious)
The starting zone always has 1-2 dwells, a prison, some creeps, easy-to-break piles. Wood and ore. In the labyrinth there is no wood/ore; you have to fight through. Random mines are all gold for now (Zone contents are mostly described in the diagrams, I won't repeat them).
Treasuries can generate 20 minors or 10 majors, for example. 20 gargoyles or 2 Dragon Utopia. The numbers are illustrative, but I think the point is clear.
In every zone there are enough freebies as well as piles that require breaking through; it's always profitable to send left heroes in there, plus for scouting.

2. Smile. A small, linear template. There is one exit. It must be broken through by the 9th day at least, sometimes they hit it at the end of the 1st (check who is there; sometimes you can take a rest or plan your skill-up and initial construction) — procrastination is like death). From the next zone there are 3 exits. The guards in the treasury are stronger; usually, you can't break through immediately, but it sometimes generates good loot). Zone 1 is urban plus wood/ore. It leads directly to a similar urban zone of the opponent. The second is also a direct resource zone with all mines. That's where they usually clash for the first time (resource or urban). Usually on the 4th week (3-6).

3. Spider. A medium, linear template (though you can wander a bit in the intermediate zones)). There is ГО. Often it can be broken through by the 6th week (skilled players by the 5th)). Besides that, there are 3 exits. 2 exits lead to zones with one not-so-strong guard, but usually, it can be taken on the 5th or even 4th week. These exits lead to dead-end treasuries. But one of them is "tasty") there are artifacts, often majors, and Dragon Utopia frequently appear there. The other is mediocre—mostly creeps and useless artifacts. You won't know which is which in advance)
The 3rd zone from the starting area has 2 exits leading to similar intermediate zones. In each of these 4 intermediate resps (3,8,9,10 on the diagram), there is a gold one (random). It's also present in zones 4-7. People often come here to feed) Also, people sometimes break through to battles here if not via ГО (not all races can handle titans)). Often the first meeting is on the 6th—via ГО or intermediate zones. Usually, by the 5th-7th, the alternative is either to hit ГО or the second treasury, or to feast in a good treasury, or to "rush" through the intermediates. Without chains from the 6th week, or even 5th, or a portal to the city, you can't)

Phew. I'm going to play; I'll finish writing later, or maybe someone can help?)