I would like to see a photo of yours. What is the brand name?
Simple principle, so there are several. Home Depot had the ones we are using.
Start here, do your own due diligence, based on type of environment, trees & such where YOU live.
Top Gutter Guards of 2020 | ConsumersAdvocate.org
As to overflow in torrential rain?
"BFD". "The wise" also have a drainage bed at ground level to divert SURFACE water away from foundations BEFORE it soaks down to the drain at the footer.
Clean that with an ignorant leaf rake or leaf vacuum/shredder. I never saw the POINT is blowing leaves away... so they could just blow right back again.
That's nothing more than a socially acceptable - if rudely noisy - form of public masturbation. Worse? Too-often "hired done".
No fear.
Looter-lie-bore-alls get elected, it will be "free", like everything else. At least until they run out of "OPM", about three weeks before they even
start to re-allocate already-scarce ass-ettes.
WTF? Nobody understands grocery-store 'rithmetic these instant-gratification ear-bud and free drug days?
Darwin - and the Devil - must be getting ready to FEAST! Again.