There's also the "intermediate" one: Emby.

Not all features are free, so there's a subscription or one-time payment mode similar to Plex, but it has less bloatware than Plex.

Jellyfin is always free, but it's missing a ton of useful features, especially relevant the client compatibility part.

Emby does great in that department: you can install an Emby client in almost any device out there, reducing or even eliminating the need for video transcoding.