Locked myself out from ssh access on a RPi4
 

While I was configuring wireguard, I ran the command

However I assume that I also had to run

Now after reboot I locked myself out of ssh access.

My RPi is headless and I don't have HDMI/keyboard, but I can mount the disk to my ubuntu laptop.
I was thinking that I could somehow configure the firewall and open port 22 again by editing a file in the disk, is it possible?

I don't have my RPi handy at the moment, but to disable firewalld, I think you can delete the symlink:

/etc/systemd/system/multi-user.target.wants/firewalld.service

This is the equivalent of doing:

sudo systemctl disable firewalld

reenable the firewall after it's up and you have fixed up the entries.

Actually I had to delete ufw.service, but this solution worked, thanks!