Self-hosted is not a way to make things free. Just lower cost than subscriptions overall. Using the full *Arr suite, with Usenet, your own hardware, and client boxes gives the users better control of the content they watch, but requires a nominal input of users time (plus some technical expertise), as well as an investment of some money both one time and annually.
Infuse’s lifetime time cost, when viewed in light of the total reduction of subscription cost (and an improved control of content) is worth it. I would definitely not pay a monthly amount to infuse, although it’s possible.
So far as Jellyfin’s app… As its free, I have low expectations. They fact that the developers have paid Apple for the SDK and put it as a free app on Apple TV and iOS is incredibly kind of them. They have a fair amount of code to look after and open source developers rarely get enough love or money.
VLC is a great way to work with AppleTV, if you are willing to trade a few more clicks and less meta data for being free. It is by far the gold standard of being able to play anything.
The file format issue, plus the simple interface (especially for older less technically inclined) makes infuse worth the $100 lifetime cost (especially with family sharing).
What hardware are you using for your LibreELEC? Pi 3,4,5? With an external drive?