The setting is made to make sure that you don't gain level experience upon reaching level 100 so that you would still need to make them legendary at Level 100, however, there's also the fact that the caps are maxed at level 500 with the exception of Enchantment Charge level cap of 199 because it ends up being broken once you reach level 199 with Enchanting.

You still get more experience for your skills, but not for your level so it would work like you didn't even have one if you maxed all skills out without making your skills legendary.

Though, I fixed it at level 500, and you can make your skills legendary even at level 100. The catch is, they will reset to level 1.

So, the biggest question is: Which is more important? Skill Level or Character Level?

I've already included the files needed for the Uncapper to work.

However, it conflicts with Custom Skills Frameworks for some reason. So, I don't recommend the idea of using that.

There's plenty of similar effects as leveling skills past level 100 is just the same as adding bonus effects like Legendary Skill Bonus.
However, if you're looking for an actual mod that increases your skill level past 100, then Permanent Legendary Bonuses is for you. Just don't turn on survival mode because it has its update interval rate and it will sometimes not take effect immediately after you changed location when you've received a health reduction effect under cold weather. Of course, I don't recommend pairing it with other Survival Mods.