Piracy: ꜱᴀɪʟ ᴛʜᴇ ʜɪɢʜ ꜱᴇᴀꜱ

Sorry I can't help with your question, but I wanted to ask what features you feel Jellyfin is missing that is keeping you on Plex? I've made the switch, and actually like Jellyfin better.

Real-Debrid is great. I use it for streaming, but I honestly use it more often for pirated music software downloads. Instead of having to go through 30 Rapidgator or Mega links or whatever bullshit, it handles it in one place.

I've used real-debrid in conjunction with the seren add-on for Kodi for years. I have the same setup on all my PCs, my phone, my Chromecast. I would say it works identically on everything but I had playback issues using the Kodi app on my Xbox (well documented issue related to that system)

1. No, you just scrape the debrid cache on demand upon selecting an episode/movie, as long as someone has already cached that release it'll just start streaming. If not, you can add it to the cache inside the add-on, rescrape and try again
2. There's no encoding happening, it's just direct streaming whatever release you selected. For release of duplicate titles when you search it will show the IMDb/tvdb thumbnail and you just choose the one that looks right. The only releases that weren't exactly what I was looking for was when Barbie just came out and some cam rips were floating around, the first result I scraped was for the animated Barbie Netflix series. No porn, I'm confident enough of that to have set this method up for my mother also.
3. Sounds redundant. If you wanna try this method for ease of use, a simple netflix-esque experience for any content, there is no comparison. If you wanna spend time watching your logs auto scrape the episode you're waiting to drop, this isn't the method. The only mechanism needed for routing your search to a matching file in the debrid cache is scraping a magnet link (via a search, or trakt recommendations etc) which matches a file previously cached on the server. "It just works"
4. Not if you're using a standard implementation with A4kScrapers. Google how to set up seren on Kodi. You may run into some P2P release for older stuff, for most people this is totally fine

All in all as someone that has pirated music, tv shows and movies for several decades now it actually aggravates me how user-unfriendly the Plex/emby/jellyfin experience really is. I can certainly understand people getting enthusiastic about a new hobby of library management, but that shit gets old and I just want to watch my shows. The only reason I can imagine why people don't do this is because it costs money. I struggle to imagine how these same people aren't already paying money for tv/movie content and getting way less value/$ to boot.

As a honourable mention I authd this setup on my mother's Chromecast to my real-debrid account, and we have no issues both using it simultaneously. However, one time when I was downloading a torrent using the debrid on my PC with VPN, while streaming on my TV without VPN, and my mother also simultaneously streaming in a different city, it booted us all off and I had to reauth. No issues since, mum calls it the dodgy box

Real Debrid is awesome, I have a jellyfin server setup but it's only for friends/family and Anime (because it's hard to find via scraping debrid.) If I want to watch any live action movie or show I do it via kodi and seren, that way I can watch 4k hdr bluray remuxes without having to store 50GB+ files for something im gonna watch once

You can test the waters and just add a debrid service as a download client to your Arr setup with RDT-Client. It works just like a regular torrent client in that case.

After short research, I think, that the change of takedown is bigger with debird as with usenet due to the decentral nature of the usenet. On usenet, your provider may ho down, but you can just config a new provider and continue to use your setup as is (same media manager, same downloader and same Indexer), with debird, it seems to me, that it is a very centralized service, that in theory can be nuked at any time. Please correct me, if I am wrong

What is your storage situation currently? Just trying to figure out why you think expanding it is expensive, because hard disks have been getting cheaper. Especially used "enterprise" SAS drives - the 12TB drives can be had for under $100. You'll need a $40 HBA card and $10 breakout cables as well.