The Last Guardian is an interesting case because there is already a way to play it at 4K 60fps on PS5. The only catch is that fans must already own a physical copy of the game on PS4 and most importantly, do not update it to the latest patch.
Running the game unpatched on PS5 allows fans to experience The Last Guardian precisely the way it really should be experienced. It's unfortunate, though, that there is no official way to play the game this way, especially because it is also part of the PlayStation Plus Collection on PlayStation 5.
This one hurts a little bit more because those who own the digital version of the game can't roll the game's patches back.