[2021] Skills list with NA next to them?

Could you provide a screenshot example?

No no, It's likely just an issue with one of your mods. You can, with enough levels, buy every single skill in the game (Requires level 278 currently); You're never locked out of any tree or subsection of a skill tree. The only limitation now is the level of the primary attribute required for the skill (EG: To buy rank 3 of Better Barter requires level 5 intellect)

Those two skills should be marked as 1pt to purchase.