Yes, the vast majority of PS4 games are playable on PS5.
The PS5 was built to read and run PS4 software natively.
Which method you use depends entirely on which PS5 you own.
A small slice of the PS4 library is incompatible, almost always because a game depends on hardware the PS5 does not support or on legacy services.
Many PS4 games benefit from Game Boost , where the PS5 applies its faster CPU, GPU, and SSD to titles that originally targeted weaker hardware.
Read the complete breakdown, fixes and what happens next.