I've had those popups on both our Win 10 machines, neither of which get close to the hardware requirements for Win 11 One is 11 years old. You need to to run the hardware checker program.

Reverting from Win 11 to Win 10 'should work' - but it depends on what's happened to the system since. And on everything going right!

On the subject of reversion, MS has invented a novel (I think) way of generating the scripts which revert files to their state before update: 'Reverse Update Data Generation'.

How Microsoft reduced Windows 11 update size by 40%

For more detail see also the links in that piece. You can see why reversion might not work!