I’ve never done this but I am curious: why not just use a garage door remote that’s compatible with your garage door system? OpenGarage does not interfere with any existing remote that works with the garage door system, it just provides another way to control the system.
I’m not sure what the general application would be but in my case I have an older third bay without an rf remote. I’m probably going to add a solidremote kit to it and call it good but a 433 radio would allow opengarage to add rf tilt sensors to measure door position and tie into rf security systems.
It may be easier to get an off-the-shelf 433 relay module, which comes with a remote and a receiver that has a relay built-in. It’s basically a RF controlled switch. The receiver can be powered y 5VDC. This should probably be the easiest solution for you as it does not require any software changes.