How to Configure a WireGuard VPN Connection to NordVPN on a Mikrotik Router Running ROS v7.x

[utopistis]

yes you could try adding this rule in ip firewall mangle.
add action=change-mss chain=forward new-mss=1380 out-interface=wg-nordvpn protocol=tcp tcp-flags=syn tcp-mss=1381-65535

It seems there is stability now, but ping now is higher and changing servers doesnt improve it. The thing aswell is that i tried to disable this action and the results remained the same, so prob this isnt the issue or didnt helped at all?