Possible MSD 6AL failure

Where is it mounted? The thing should be away from engine heat

Could be a coil starting to fail. This is classic coil failure, IE fail when hot, work when cold.

Might not be ignition at all but something else.

You need to acquire some troubleshooting skills. Learn to check the spark when cranking. Get tools that allow you to do this "alone." You can buy spark testers.

Understand and acquire knowledge about "how it works."

EG:

Mopar ignition switches have TWO ignition voltage supplies, one for "run" and one for "start."

Let's say the "start" circuit has a problem and you don't have voltage to ignition for start. YOU MUST check this by using the key to start.

If you check spark with the key in run, and by jumpering the starter relay, you will mask the problem, because you changed the conditions of the problem.