You could keep the Hetzner VPS with storage for faster online serving of assets and connect a second immich instance only for machine learning on your home server. That way you'd get the best of both worlds: fast media serving and higher performance. That would mean that images are uploaded to the Hetzner server, but the compute-intensive image classification takes place on your home server.

A friend suggested this as well. My desktop has a 2080 which is decent enough for machine learning.