I was bored and looked at the list of PS5/Series exclusive games and it's even shorter than I thought. Here we go
Returnal
Ratchet and Clank
The Medium
Deathloop
Astro's Playroom
Demon Souls
Yuffie DLC for FF7
The Last of Us Part 1
Ghostwire: Tokyo
Let me know if I missed anything, I even added a few remakes, a pack in game, and a five hour DLC to help pad the list.
They are basically PS4 Super Pro and Xbox One XX at this time, all you get is cleaner, more polished and better running games that you can still play on the older systems. So to answer that poster's question awhile back before it got derailed, I wouldn't put too much effort into finding a system right now.