Problem with CPU at 100% and RAM does not stop increasing

[Efficient_Good_5784]

It doesn't matter if it doesn't play it, before I had it like this on another service and 90% of the content is played without problem for the majority
If it can be deactivated, I would be interested to know how.

You have to re-encode with the codecs and containers I stated above.
Is that done within jellyfin?

The re-encoding needs to be done with an external device. As in with another computer separate from the server using something like Handbrake or FFmpeg to convert the media. You would then move the converted media onto your Jellyfin server when they have been converted.