https://larzm42.github.io/dom5inspector/
This all you need! Just click on units - select any nation you would like, and just click on national. And just read through all the lore that Illwinter put together for a unit. And they did something for all units. Some are copy paste - like different types of solders. Some give you hints about special abilities.
That was my gate way into the game. Not the mechanics, just the lore. And then the spell paths and the combinations.
Also, it makes you ask questions - Vampire Counts are cool, but only your Pretender can create them, so you need to figure out if its worth it. (It is). Of course, some spells are important, but some spell just exist because of lore reasons, and shouldn’t be bothered with.
Oh, and the wiki is so much better these days!
Welcome to illwiki! - illwiki: Dominions 5 Wiki
By the way, keep in mind, half the infantry chaff is useless in the game and can be ignored.