The “wg0” interface exists (this is created by wireguard itself). Even if the “lo” interface is not listed, the local connection works (ssh, vnc, scp, etc). Only connecting to wireguard with nftables running does not work.
I have now tried to modify the nftables.conf by inserting these parameters:
define pub_iface = "eth0"
define wg_port = 51820
in the chain input:
iif $pub_iface udp dport $wg_port accept
for the moment this seems to be working