I’ve heard the “reduced shingle life” issue, but I don’t think that’s really a problem - they get pretty hot up there anyway. The problem is when that heat seeps down through your attic, your ceiling, and your house. Preventing that increases comfort and lowers cooling costs.
And, if you want to cool your shingles - water them.
A person could in its simplest form just have a sprinkler system on the roof to chill it or better yet for the serious shielding get one of those tractor trailer reefer units, lay a grid of PEX tubing on your roof, lay another layer of OSB, tarpaper roofing paper or whatever your roof is.
Basically you are building a chilled roof that would be near freezing.
Its not as hard as you think, I build hydronic heated floors in my house, most of the stuff comes from Lowes. With a little creativity and a heat exchanger I can create a thermal shield. Same can be done with the walls.
the goal is actually not to do this on your whole house but a more discreet building like a shop, up in Alaska the pot growers use this reverse hydronic idea to shield the roof from overhead flights of aircraft with thermal scanners.