I really try to move to Jellyfin, but there’s always some papercuts that block me. Tried it last weekend again, and:

• It just can’t find most of my movies in the NAS share. They never appear in the library.
• The music player cannot play all my files. DSF files are transcoded to AAC. Also finamp streams AAC and not Opus, and uses more data than Plexamp did.

I also tried Navidrome for music. Weirdly it had hiccups playing some files, and DSF was again a problem.

I really want to get out from Plex, but I use Plexamp so much and it handles my huge music library really well it’s hard to switch :(

You should maybe read about the use cases for deduplication before using it. Here’s one recent article:

https://despairlabs.com/blog/posts/2024-10-27-openzfs-dedup-is-good-dont-use-it/

If you mostly store legit Blu-ray rips, the answer is probably no, you should not use zfs deduplication.