PC Internet connection breaks off often?

Moin So if I'm connected to my Lan cable on the PC breaks the connection ca every 10 minutes once briefly off so that is displayed as if there was no Internet on my PS4, the same happens on LAN but on Wlan everything is stable what can There are? The LAN cable is relatively new so do not think that it is broken

If that happens anywhere in your LAN, then a switch / router is broken.

What could I do about it? Do not want to buy a new router now ^^ if there's another solution

Well, if the router / switch is defective, then it must be replaced. Or you live with the failures.