Try this in tmux.conf:

set-option -ga terminal-overrides ",foot:Tc"

These overrides apply to the TERM you are using outside of tmux (where this is running).

Wanted to help you potentially avoid a wild goose chase—port checking tools won’t detect a wireguard port as open…it’s specifically designed to not advertise its presence for security purposes. Bad handshake requests are ignored, making it look like a firewall DROP rule.