It's very much a playstyle thing. I like being surprised to learn what the PCs are capable of- over time ofc I'll learn what they can do and adapt, but I definitely don't know all the player options until I have to help a player understand something ... Or if a PC is doing something and I think "now that doesn't seem right, how does that work?" and ask them to read it, or I'll check it out after the session. But I also know which players that'll tend to come up with :')
Ofc not knowing every player option has bitten me in the past when something like Tasha's comes up and a 2nd level spell trivializes 2 purple worms

"oh that's very cool" is one thing, "oh what the hell that's so busted" is another.