Mailcow Setup help

I'm running a home server on Arch Linux and trying to set up Mailcow (Dockerized). I have a static IP and configured NAT, but I just found out that my ISP blocks port 25 and refuses to open it.

Currently, I’m unable to send or receive emails. However, I can see Mailcow UI and connect using Thunderbird.

What are my options to work around this? Did I misconfigure something?