As usual Hetzner is always a solid choice - their Object storage is more than solid and comparably cheap - Personally I would not transfer to your VPS though as Immicg can get funky when latencies are too high. Just run the cheapest VM there that can take Immich.
Alternatively IONOS is doing a lot of good things as well these days,but they are slightly more expensive m
jeena@piefed.jeena.net 2 days ago
I just run my immich instance on my desktop computer and mount the external hard drive there.
I'm not sure about the speed if you'd mount a local drive or a s3 bucket via fuse.