While trying to find a way to make WSL2 more usable, I stumbled upon this categorical statement that it was not possible to run ZeroTier under WSL2—
(I have restricted links - google "Unable to install in Windows WSL2")
First I installed Docker more or less as explained here
Then (because it is so much more user friendly than Docker) I installed Portainer more or less as explained here
Finally, I created a Portainer stack (docker compose) from a docker hub distribution more or less as explained here:-
hub.docker.com/r/seedgou/zerotier (restricted links again)
One caveat: If you install zerotier on the host windows machine afterwards, you will need to stop the container first, otherwise you the “waiting for zerotier service” problem.
After that, I now had a fixed address for my WSL2 that survives restarts, can be plugged into DuckDns etc. Makes SSH much more usable too!