CircleCI supports macOS runners and has native support for rerunning failed builds with SSH access. So just setup a job that always fails.
[1] https://github.com/marketplace/actions/debugging-with-tmate [2] https://github.com/marketplace/actions/ngrok-tunnel
I've never really understood Hetzner's offering, I can get paying €2.4 for a quick one off or a once a month build but I don't get how €98 + €49 per additional month is better than buying a Mac Mini on a payment plan.
[1] I believe this is the closest publicly documented effort, and it's a year old: https://news.ycombinator.com/item?id=25064593
It can be hard to justify $15.60 every time I want to test some random thing. Not to mention I seem to recall you can't actually cancel a reservation till the 24 hour window is up, so you need to remember to stop it the next day, or automate that action somehow.
"Amazon EC2 Mac instances are available for purchase as Dedicated Hosts through On Demand and Savings Plans pricing models. Billing for EC2 Mac instances is per second with a 24-hour minimum allocation period to comply with the Apple macOS Software License Agreement"