What year is your bike?
That was an interesting read, did you ever test with new plugs, if not you should (they can work in atmospheric pressure but under pressure the flame is blown out).
When you have the timing light installed aim it at the timing marks to see if the plugs are firing when they should. You can add a dot or stipe of white paint to make them more visible.
You have spark and fuel but they might not be at the correct time, especially the spark (a fuel charge can hang out in the intake until the valve opens).
I do not think it’s a battery voltage issue, the starter would be disabled first if that was the case.
Check timing and replace spark plugs.
