https://wccftech.com/playstation-one-games-tested-ps5/

The first available PlayStation One games have been tested on PlayStation 5 ahead of the PS Plus re-launch, and the emulation appears to be quite good.

Ahead of the launch of Sony’s revamped PS Plus service, the first few games have started surfacing on the official Malaysian PlayStation Store. As already revealed by Sony, some of these titles appear to be available for individual purchase, including Oddworld: Abe's Oddysee, Worms Armageddon, and Worms World Party. Ridge Racer 2 for the PSP, however, isn’t available for individual purchase outside of the PS Plus Premium tier.