Thank you! That 'delayed_on_off' did the trick. It was interesting, it was only bouncing like that on the door closed sensor. But I added it to both ends, just in case. I also upgraded my door sensors, which may mean it doesn't need that delay, but I added it anyway.

Old sensors:

https://www.amazon.com/dp/B01MYTE7OQ (had to be within 1/2" to work)

New sensors:

https://www.amazon.com/dp/B07H92R1S9 (works a couple inches away)

Regarding the end-stop, my integration is only to control the existing garage door opener system, it looks like yours is completely self-built(?), which means "no, it's not required for the door to work".

On your system, I see an open button on one pin and a close button on another. So you can open your door, stop it part way, then finish opening it, right? Mine is really just a toggle. If the door is opening and you stop it, the next button press the door will close, so if you want to finish opening it, you have to stop it again, then start it again, and it will finish opening.