The remastered version looks set to have improved textures and models, run in 4K and ultrawide (on PC), better loading times and other QLD improvements. Bloodborne in particular ran quite poorly on the PS4, so it’d make sense that Sony would want to bring it back in some form.
Where things get even wilder is that one of these YouTubers is also claiming that a Demon Souls Remake is on the way from Bluepoint Games. This has been rumoured for a long while, but it does seem odd that Sony would reveal both Demon Souls and Bloodborne at the same event, given they target such similar audiences.
Now, I said earlier I'd share more info about it. So, what I can confirm is that it's not just a PC port of Bloodborne, what was supposed to be revealed today was a Bloodborne Remastered/HD edition that was coming for PS5 and PC. I don't know of any release date as of yet.