Too many is for your countable nouns, basically everything else!
I have too many phones! Which one is ringing!
They have too many children, how do they remember their names?
We have too many reports to do for tomorrow.
I have too few friends, I really need more.
There are too few interviewees, so I can’t make a decision.
Excellent work. Now we need to do a test… you can never have too many tests! 📖