When it's starting to fail, does it (coil) get too hot to touch? If so then it's bad.
Could also be, the fuel vent line is clogged. Bugs get in and make nests.
The pickup in the tank is clogged.
The filter is dirty or full of water.
Ethanol?? It's delaminating older hoses and can melt the inside of the hose.
Check for soft, mushy or slimy hoses.
I have checked most of the things you mentioned - that is why I have headed toward the coil. Specifically,
Did not check the vent line. Where is it and how to check?
Tank pickup is good as I drained all the gas without issue.
Fuel filter replaced AND fuel pump replaced
I drained (above) to check fuel - it is (and was) perfect Also I added 30 gallons of fuel without ethanol
Replaced all hoses after draining fuel
So it seems we are thinking similarly - I just don't know about the vent.