You can slow the PAL video frame rate down to 24fps or 23.976fps without re-encoding the source or downgrading to 480p by using tsmuxer. Done this hundreds of times myself.

Assuming your PAL DVD rip is contained in one .vob file, simply drop that file into the program window and check the box next to “Change fps,” which enables a drop-down menu next to it. Select the frame rate you wish to convert the video stream to and save the corrected video to either a .ts or .m2ts container.

I can’t speak for compatibility in other NLE programs, but I’ve never had any issues importing video I corrected with tsmuxer into Vegas Pro. Works like a charm.