When I framed my basement there was a long delay between framing and
securing the drywall which resulted in some stud warpage.

As a result there was some stud prep required before drywalling that I
hadn't expected.

Take a long straight edge to determine where the wall is flat and
where it isn't. Less than 1/8 inch difference shouldn't be visible.

If only a few studs need to be moved you could perhaps whack em a few
times and drive a couple more nails.

If you've got to remove one - a sawzall can cut the nails and you may
be able to shim and resecure the same stud.

If the stud is warped, a neat trick is to sawzall through half the
stud on ann angle and drive a screw to pull the cut together. This
will take one large curve and make it into two or three smaller ones.