Garage doors can kill people. I (literally) wouldn’t touch the controller. There’s a lot of safety stuff built into those.
Instead, the standard approach such as used by the Meross device just makes a lot more sense: parallel the existing remote operation, and you preserve all the built-in safety features of the controller itself.
Plus using something like Meross (there are other alternatives from other brands), preserves the UL safety listing, which will keep your insurance company (and in some cases your homeowners association or township) happy as well.
Meross as a replacement for MyQ (2023)
Any DIY project attached directly to the circuit board of the garage door controller probably violates both warranty and safety codes.
I’d save that kind of project for, say, holiday decorations. Not a garage door controller.
JMO, of course. 
just as one example: UL 325 requires that if the obstruction detection triggers twice in a row, the remote must be disabled until the hardwired wall button is used, which is intended to mean that a person with line of sight to the garage door checks what the obstruction is and clears it before trying the garage door again. This keeps automated/remote controls from slamming the door back down multiple times on the same obstruction. (This also protects against Automation glitches.) If you wire in a smart switch which can be activated remotely to the wall button, you are then bypassing this safety feature.