PS4 games on PS5:

1. First party PS4 titles - received free patches unlocking the framerate for PS5. Yay, now you can enjoy the same title with 60FPS for FREE on PS5. Example: if you bught TLOU PTII on PS4 you can play that same exact copy in 60FPS on PS5.
2. Remakes/remasters - 10$ upgrade for owners of originals, adding new graphical assets, new game modes/content etc, and an engine swap in case of remakes.
3. Tons of 3rd party games offered free upgrades and cross-gen bundles so you'd automatically own both PS4 and 5 versions.
https://www.pushsquare.com/guides/ps4-to-ps5-all-games-with-confirmed-free-upgrades


Switch 1 games on Switch 2:

1. Some Switch 1 games - will receive a free patch (very small amount of titles so far)
2. Switch 2 upgrades - essentially framerate/resolution patches with a few gimmicks sold as next-gen upgrades. The patches are relatively simple to develop and don't even come close to the scale and complexity of Sony's PS5 remasters and remakes. Example: Zelda TOTK Switch 2 upgrade unlocks the framerate/resolution for Switch 2. This patch should've been free. But they've added a few gimmicks, does a map navigator and the option to share your builds really justify calling it a next gen edition?