The main page doesn't mention Terraform explicitly (except for the user feedback section). Are there plans to make this compatible with e.g. AWS CDK or Pulumi?

Yes, we have got quite a lot of requests for those. On the roadmap for sure!

ngrok (https://ngrok.com/) and localtunnel (https://localtunnel.me/) come to mind.

Localtunnels is close to what I want. Just would like it to be in form of a service run by volunteers, so I can have confidence it will not be corrupted by the possibility of profit in the future.

Or you could just setup a cron-job that runs a script that changes the SSID (e.g. using UCI)?

Thx for the suggestion, I have actually done this in the past