I have a Wireguard server running on a remote OpenWrt modem my mobile connects and works okay as did my laptop when it was running W10. Upgraded the laptop to LM22.2 and no joy with the same configuration. I has similar issue the other way again from a Mint desktop to my home Wireguard server running on a Pi4B, again the mobile and the W10 laptop worked. So I am pretty sure it is a Mint issue not OpenWrt or Wireguard specific.
I've managed to get it working using OpenVPN albeit I had to modify the configs from
tls-version-min 1.3 to tls-version-min 1.2 cipher AES-256-CBC to cipher AES-256-GCM
Is there a similar gotcha with Wireguard? Whilst I could find details ref the above changes I cannot find anything hinting at similar for Wireguard.