Completely true… you should attempt to do streaming over the Cloudflare solution as you will get banned. I would also guess performance might not be great since again the bottleneck is the Cloudflared/Cloudflared container on your network sending and allowing all the data to and from Cloudflare. Fine and dandy for normal work but I would think streaming media and even trying to do something like high end remote video editing is not going to fair well over it unless you give that a lot of good resources and that device itself has a really good network adapter connected to a good switch.
I mean you will still have a bottleneck local hosting and streaming through your reverse proxy anyways since it goes through the SSL encrypted hosted site and if it is Plex it is totally pointless to do other than for hiding purposes like your server is cloud hosted. You are essentially SSL encrypting the SSL encrypted traffic. You might as well add an additional Wireguard VPN around all of it and then attempt to stream something and watch it all buffer and come back and ask everyone for help.
I bought the lifetime pass many many many many many years ago when it was cheap… dirt cheap and love it… my family uses Plex daily. We have no paid streaming services and no paid TV services just Plex. Only thing I cannot make work in Plex well is IPTV as xTeve just sucked and was constantly dropping channels because the Channel Guide Feed would have an issue when it was refreshed and Plex would say “sorry no guide no channel” and just mark it not available. It was a weekly fight.
I have over 150,000 FLAC audio files and tons of 4k movies and TV Shows. Kids love to watch their shows and movies as do my wife and I.
I have Jellyfin setup for IPTV and have used it off and on for years. The iOS client has remained “okay but clunky to me.” I mean it works, but really gets no love no real updates and while I dont have a great need for Transcoding with Plex it is nice to have that feature. The Roku client is the same. I have mostly Roku TCL 4K TVs and streamers and that client has looked the same and clunky for years. Again it works (explodes occasionally but really it does work pretty solidly) but Plex just brings so much more to it to the media you are watching.
Would I pay the higher price for PlexPass now if I did not own it or just use and live with JellyFin? I would most likely still pay the price (on sale when they send me the discount code) and get the deal. It is just worth it to me.
Also the home user lock down features like I can share specific libraries or just specific TV shows or movies with my kids I like with Plex. Not sure If I can even do that with JellyFin (never researched it so it might be there).