It doesn't really matter what the skill checks are or if she sucks only a little bit or a lot compared to Karlach.
The point is that the permanent 6 point stat debuff does not serve any purpose except being an illogical nuisance for the rest of the game. One that encourages you to remove Lae'zel from the party when you just got deeply involved in her redemption story. It's entirely backwards.
Skill checks aside, the game doesn't let you remove her from the machine. You wouldn't need a skill check for that. The whole scene and the outcomes are badly designed. It's idiotic the rest of the party are just standing there trying to find clever ways to convince her to get off the machine when she clearly doesn't know what's good for her, and they could simply remove her at any time to save her.
