Connection crashes under high load?

I have a relatively good PC on which all games run smoothly. However, every time you open certain games (GTA5, Fall Guys, Fortnite, etc.) the LAN connection crashes and can't be reconnected and has to be restarted. What can that be?

Cable checked? Lan cables slip out very easily, especially with broken ticks. Router? Modem? Cable type? DHCP? Ip6 or 4?

Cable is new, but I've already tried different cables. It's not a router either, everything works fine on any other device. However, the connection is only disconnected under high loads, otherwise not, i.e. During normal use.