A fanmade site is your best tool for making the most of PS5 backwards compatibility across hundreds of games.
The succinctly named backwards-compatible.com currently has a searchable database of 577 games. You can punch a title of a game into the search bar to find something specific, or if you're just looking for something in your collection that supports HDR and "performs best on PS5" you can select a filtered view that will show you everything that meets those criteria. It also includes a dedicated tag for games that currently have graphics issues when running on PS5, which is handy to know ahead of time - or on the flipside, which games will run at a locked 60 frames per second on PS5 for nice and smooth gameplay.
The site was built on data assembled by ResetEra user Liabe Brave, who has been analyzing videos and screenshots from PS4 games running on PS5 since launch. The list is always being expanded and updated, and with the sheer quantity of PS4 games out there to cover, it's a massive effort. And a really handy one for the rest of us, who just want to find out how Gravity Rush 2 performs on PS5 before we go digging around for our old copy of the game.
Playing PS4 games via backwards compatibility has been a great boon while we're waiting for more next-gen native experiences, but our early look at PlayStation in 2021 indicates we'll have a whole bunch of new stuff to play by this time next year.