If you can tolerate screens some times but not others, your screen difficulty is not permanent. Your highest level of screen function may be your limit but your reduce screen tolerance is not. There is likely some other stimulation that is reducing your ability to tolerate screen time.

It like complaining. When I am holding my child on my lap, I can only type 15 words a minute. When I have nothing on my lap, I can type 50 wpm. Is this 15 wpm a permanent limit ?

Yes it is but only when the other factor is at play, (child on lap). But, over time, the child can learn to sit quietly on your lap so you can type faster or even sit next to you where you can type at 50 wpm.

So, yes, you may need to accept that in some situations your screen time has a limit. As you learn to work with that, your tolerance of screen time during those situations may slowly improve.

btw, Many get totally burned out by video games with the crash not showing up until the next day.

I guarantee you that there is another factor at play when you crash. You just need to figure it out.

Be encouraged by your maximum capability and work to close the gap between your max capability and your limited capability. Even healthy brains have times where they have limited capability.