I thought zerossl used let’s encrypt behind the scenes (for their free certs at least).

Edit: they don’t mention that on their website, perhaps they don’t.

Great in theory, not so great for simple automations like seeing of people are home based on connected MAC addresses instead of relying on an app (that can’t even run on the background consistently on modern mobile OSes).

Well, at least they tell you to not trust it for production in it’s current stage I guess.