Sorry, I wasn’t trying to suggest that it was beyond your capabilities but I would not equate the complexities and potential risk of a gas water heater to a garage door. I would not advise anyone to open and tinker inside the controls for a water heater or any other device for that matter that has the potential risk of serious damage and/or injury/death.
Installing external controls for a device like a garage door is one thing. It is designed to allow multiple controls and you are not touching the built in safety mechanism(s) of the device. I have an Arduino/ST controller setup on my garage doors that gives me control through ST as well.
It’s entirely another matter to open a device that is controlling the regulation and ignition of an flammable/explosive gas. The potential, however small, of inadvertently damaging the mechanisms inside a gas water heater could lead to disastrous results.
If nothing else, surely tampering with the water heater would void any warranty. Also, you could potentially run into liability and insurance problems if anything negative were to ever happen.
I would explore the advice presented by @codytruscott “recurrent reset situations indicates the need for a service call”