Hello!
The Temporal Upscaler Visualization does not seem to be present in 5.2 Preview2, does it need a command to show up or config change?
Sadly we dicided to integrate from UE5/Main to 5.2 right after 5.2 Preview 2 that is why it is missing. 
But you can find the change on github in 5.2 right here: https://github.com/EpicGames/UnrealEngine/commit/2c492529cc0137023c2fced237f7225086b0c985