Only The Last Guardian disc owners appear to be able to play the game at 60 frames on the PlayStation 5.
In case you were not aware, SIE Japan Studio and GenDesign launched this adventure game without setting a frame rate cap initially. Unfortunately, however, they turned off this option with a subsequent update and turned the rate down to 30fps.
However, NX Gamer posted a video that crosses that hurdle, confirming that game disc owners can take advantage of the PS5's great potential via disc version only.
Therefore, if you pre-order the digital version of the PS5, you likely won't be able to play at 60 frames at all - unless Sony urges SIE Japan Studio and GenDesign to raise the frame cap again and bring things back to life. First of all.
It's not clear if Backward Compatible PS4 games will have the same problem - but we now know that disc owners can somehow bypass that.