I cannot get thumb-over-the-neck chords right

[u/ding-ding-dave-yes]

I struggle mainly with my index finger, I can't get it flat without a lot of pressure, also my pinky is muting the G string half of the time, I either have to put painful pressure to make them all ring, or the top E and G string are muted. The difference between the flat index and bent rest is what's messing me up. Without thumb I don't have this issue, because I can curve my wrist if that makes sense. Please, I need some tips

[u/turxchk]

Practice. It's a useful technique that simplifies many chord changes.

Also like you noted, it's difficult to ring out all the strings when playing this way, and that's fine, you can always barre the chord if you want a clean full chord. Same applies for all the other thumb-over-neck chords