I guess I would go with Hellblade 2's reveal at the Game Awards over the Unreal Engine 5 tech demo. Both look graphically impressive, though.
It's weird because Hellblade 2 is in-engine while the UE5 tech demo is running in real-time as "gameplay." Honestly, I don't know what is supposed to be more impressive.
I picked HB2 because it looks to appear more substantial and something that's coming in the near future. The UE5 demo on the PS5 looks great, but as people have said, its a look into what games can truly look like when they live up to the full potential of the engine. Whether that's applicable in 2-3 years remains to be seen. I know this example is sort of not that relatable, but I'm sure people remember that FFVII PS3 tech demo back in 2005, salivating on what FFVII could look like in, at the time of the PS3/X360, modern tech. It only took more than 15 years later, and another generation, for that dream of an FFVII remake to come true (at least 1 part of the game :P).
UE5 appears to have some interesting potential. I'm not sure how much in terms of gameplay, though. Hopefully we'll see something cool about it in the near future.