I think I get what you’re after - the problem you’re having is, if you autoseek a sample, and start messing with pitch, it messes up the speed of playback, yea? (and you really want each individual slice element to get pitched up/down/what have you at your command).
Another thing to try might be dBLue’s amazing amazing (AMAZING) tool, copy slices to pattern: https://forum.renoise.com/t/new-tool-2-7-2-8-slices-to-pattern/31593
That way, you could take your sample, slice it up, and automatically lay out all the slices in the pattern editor. Then, messing w/ pitch via macros doesn’t affect the speed of the overall sample playback, but you (essentially) get a sort of auto-seek function (because you can start playback wherever you want and you’ll still hear the sample).
Again, might have totally misunderstood, if so, ignore! 