speeding up bpm sounds fine. no prob there

but slowing down gives some artifacts

heres what i do:
resample into the loop capture to even off the edges so it doesnt drift

then i layer 4 versions of that resampled loop with different filter settings LP to get the kick, BP/HP for the mids, and HP for the top end

what happens is the slight human error overlaps those annoying skippy sounds and you get a much more smooth result

Thats a really good idea, thanks!