Tactics for playing as the Dwarves.

Yes, light magic is indeed good, but instead of focusing on attack, I prioritize defense; I don't know, I just like it more, but in this situation, focusing on attack is definitely more suitable.
First, I level up defense, definitely up to the maximum; that's the main thing. It makes it much easier to defeat neutrals, and we don't need anything else for now.
Then, you need to decide what to prioritize. If the game will be long, it's better to try to get Education because of the magic attraction, as light magic consumes a lot of mana, and we can defeat neutrals without it. But if the map is small or there are serious neutrals that need to be dealt with, then we take light magic first. I only take Leadership after that, as it's not as useful without Retribution.

Yes, Readiness is indeed a useful skill. I first felt its benefits when I leveled up with humans. Cerberuses, furies, and other creatures that fight without taking damage are easily defeated. I haven't been able to do it with dwarves yet; either the necessary perks don't appear, or I have to choose a perk from defense instead of something more important. And attack, as Player already said, is important for dwarves because of their low attack and small damage output (by the way, if you're going for Chaos, you can take Mass Haste in attack and cast it first). In my opinion, the relevance of Readiness strongly depends on the race of the opponent. When playing against a Necromancer, it's not beneficial to sit in defense: they'll throw Chaos spells; the Necromancer will cast a couple of Mass Curse spells, and then something like Berserk/Dominate, etc. If the enemy learns or can learn Darkness, then taking Readiness is a big risk, as they might cast Mass Dispel. I take Education as soon as it's available. What bothers me about magic is that the magic I planned in advance is given very, very late. I recently wanted to level up in light magic, but I didn't have it by level 15. But on level 1, I got Chaos (and it didn't appear again), and somewhere around level 10, I got Summon...

I would really like to hear how others conduct battles because online dwarves passed me by, as I've been stuck with a slow internet connection for 4 months, and I only started playing as dwarves after the Horde expansion.

For now, I won't give any advice on this; it needs to be tested in practice, and playing against the computer always turns out to be a bit strange... We have a game planned with Vaishan; as soon as we play, we'll post a replay. There will be new food for discussion: analysis of mistakes, highlighting successful tactical maneuvers, etc.

Added 4 minutes ago

Hmm, did attack and defense reach 20? How is that possible? In the early stages of the game? I'm not doubting it, but I'm just curious where you can get that much in the beginning... Especially attack. Please explain.

By the way, I didn't realize it right away. The easiest way to raise stats to such values right at the start is to level up an attack and/or defense hero. I don't know if Alucard had one, but in general, 20 is not the limit. But this leads to a corresponding combat style, which may not always be truly useful (remember the devastating Fireball of the Sorcerer combined with the Fire Lord).