When is the last time you reseated ribbon cables and some of the power connectors in the back box? Do your voltages check out at the board and at the coils? When is your end of switch engaging at the weak flipper? At the very end? Is it even engaging and thus the coil getting hot? Also, what are the magnets you are talking about. I assume your flipper board optos are clean given they are newish.

I see what you are talking about. That looks like a terrible design. I think the thing with the original design is the two different optos actually measure the speed of your button press which translates to slightly variable power at the flipper ( after years of playing the game that’s what I feel anyway). Also that’s my theory based on seeing the physical design. Is there anyway to get the originals and not those goofy magnets? That would be my first move after everything up above. I suspect given your magnets have fallen off and have been taped, your board is permanently measuring a feathery flip.

Don’t hesitate. https://www.marcospecialties.com/pinball-parts/A-20207-P

https://www.marcospecialties.com/pinball-parts/03-9001

Double check these are correct but I’m 99.9% sure this is what you want.