Personally I still use sliced record buffers. Yes, if you change tempo then the slices will be out of sync - but only as expected, i.e they will be the same length as they used to be. Any time I record to the buffer at a new tempo i’m aware that it will turn out wonky, which can sound interesting, otherwise once you’ve got the shortcuts down it doesn’t take long to [TRK + BANK] -> slice menu -> create slice grid while playing.
Remember to save and assign a sample to the record buffer slot to keep your slices in place through power cycles.