I'm no expert, and so far I've only flown part 135, piston and now jet.
I understand the contrast can be huge coming from a CFI environment or even coming from any GA job.
The truth is that even though the job itself is "easy" once you're comfortable with the aircraft and the operation, the transition can be pure hell. I still have nightmares about my initial at flightsafety lol.
Each person is different, and some people need to man up and grow a thicker skin, facts. Some people maybe had bad luck too, but that's life. If someone is studying for 7h a day and can't memorize systems, then try studying for 8h, it is what it is. If your sim partner is really bad, oh well.... You'll have to do your part and 50% of his haha, which is also how things work in real life sometimes.