NextPVR provides IPTV support for Jellyfin/Emby/Plex
Once you've enabled it in your account, launch the app via your dashboard.
The default login is:
adminireadthedocsSee Interconnecting Apps for details
No, you can't currently. Although NextPVR thinks it has access to a /recordings and /buffers folder, these are limited to 1GB, and exceeding them will cause the pod to restart.