No, that is not possible with the sabayon architecture. It needs to store letsencrypt key/token for all domains, and stores them as config vars.
You'd have to store them in a database for example to avoid having to restart the app.
But that wouldn't be a good solution either, as letsencrypt will not allow you to have more than 100 domains under the same certificate.
All money put aside, I'd definitely prefer to be maintaining a startup (it's not dead since money is put aside) than carving figurines in a garage.
Everyone his hobbies. If your hobby can land you some money so you can get a roof and some food, then you're already a good way to becoming an happy man.