1 default via 10.11.12.1 dev tun0 proto static metric 50
2 default via 192.168.1.1 dev enp0s31f6 proto dhcp metric 100
3 10.11.12.0/24 dev tun0 proto kernel scope link src 10.11.12.35 metric 50
4 87.101.92.170 via 192.168.1.1 dev enp0s31f6 proto static metric 100
5 169.254.0.0/16 dev enp0s31f6 scope link metric 1000
6 192.168.1.0/24 dev enp0s31f6 proto kernel scope link src 192.168.1.34 metric 100
7 192.168.1.1 dev enp0s31f6 proto static scope link metric 100
Line 1 is a default route via VPN (interface tun0) with a lower metric, therefore higher priority, than the other default route via your router in line 2 (50 vs. 100). This gives the VPN route priority. Therefore I can confirm that everything is routed through the VPN server. The only exceptions are line 4, the VPN server's IP, and line 6 which is your local network.
IPv6 routes are negligible here; you don't seem to have IPv6 connectivity in your network.