Thanks for the reply!
So I ended up getting it working by changing the network wireguard is using to 10.150.1.0/24. I am unsure why my Docker containers didn’t want to chat with the clients using the other network range, but this worked.
In addition I discovered something strange. The Mikrotik web gui just flat does not work properly for me when I add a public key for a client. If I add that exact same key via CLI, it works fine. Strange incompatibility with Chrome on my machine, or a bug, or something, but it’s reproducible 100% of the time for me. An export via CLI after adding a client via the GUI shows the key looks exactly the same as it does when I added it via CLI, so who knows…