I acquired a PS5 from my son after I got him a Pro model. I'm not a gamer so my experience with a PS5 is nil. So since I'm not a gamer I am procrastinating about even getting my own PSN account. What I am asking however is my older granddaughter has a PS4/PSN account. So I'm guessing she could simply use her login to play games on my PS5. I've Googled an apparently you can have more than one account of the same console. But a game she downloads via her account won't be available to my login.
I've put it in my granddaughters bedroom here. It's also got a 2 TB drive installed. She doesn't stay here as often as she used to because she big 18/Senior now. But sometimes she stays when her younger sister is staying with me and they play games(Fortnite) together. The older one on her PS4 and the younger one on PC.