I switched to jellyfish last year. Though I didn’t try to get watch history over. Jellyfin should handle your file structure very similarly to Plex, so if what you have now works, it should work on jellyfin.

If it’s only you and you’re only using phones and laptops outside, then you can just skip reverse proxy and all that and just VPN into your system. Wireguard, tailscale, or zerotier are good options with simple easy setups.

I think you should just give jellyfin a try. You can run it at the same time as Plex, so you can just play around with it and see how you like it.

I love the Moon+ Reader app. Tons of features. I like that it has a dark mode and you can set the brightness very very low (on OLED) so reading in the dark at night is comfortable.