On the loops / sampling front: I always thought RAVE [0][1][2] was a very interesting approach, that really embraces latent spaces and sample/stretch type approaches in the waveform space

[0] https://github.com/acids-ircam/RAVE?tab=readme-ov-file

[1] https://www.youtube.com/watch?v=dMZs04TzxUI

[2] https://www.youtube.com/watch?v=jAIRf4nGgYI