I've only played the original System Shock 2, but compared to bioshock it's more of a survival horror RPG. You level up, have a map and some common areas you go back to, an inventory and the game doesn't pause when you use it, and you pick a class at the start of the game.

So be open minded and don't expect an action boomer shooter with extras like BioShock is

They're more influenced by the storytelling than the gameplay, and I don't think you need to know much about the first game to get into two. However, the gameplay is more adjacent to something like the original Deus Ex or Thief where it's about as open as a linear game can be. You should be testing the moments you think "is the game gonna let me do that?" Because there's a good chance the game will let you.

Only played the original. My advice, is to save psionics for playthrough 2. It's super fun, but is best on another playthrough. Also, it's more RPG focused and ImSim focused than Bioshock.

strength gives you more inventory space, I can't remember if it mentions that in-game but it's naturally incredibly useful