Which magic schools should I choose for the late game? Or should I go for a specific artifact?

Regarding magic without summoning or chaos in the early stages, up to 1 month, it's difficult to defeat neutral creatures (there are significant losses, which is annoying)). That is, chaos/summoning (depending on the spells of levels 1 and 2), then darkness/light, the same applies depending on the spells. Correct me if something is wrong.