I don't understand everything, I'm a bit stupid.
But with the other PC I also had problems with jerking, stopping, don't know. The output is also 4k. Only if it only arrives with HD, does this make sense?
I had connected a 40pin GPIO DVB T2 / C receiver.
I used the software TV Headend via browser, which is also available in Kodi for post-installation.
There it was, increasing the graphics memory the problem, I doubled it and everything went smoothly.
How written the 40Pin GPIO via USB converter ???