Today i've got myself Blackmetal Axe and wondered how much of improvement it is.
Checked numbers and what i see? With my 14 axe skill i deal 32-61 with base 95
So basically, you really need to level that skill to be effective.
Source: https://www.reddit.com/r/valheim/comments/m2bzgb/til_different_gear_tier_requires_different_skill/