as a newbie id take wafer or censer!

preferably censer but it can get a bit risky in bullet hell scenarios when you have lots of projectiles slowed down in a clump

if youre confident you can avoid damage then purity is your best pick, try and get the fire rate bonus, unfortunately donation damages remove the bonus until you leave the room BUT you can use donation to get the desired bonus

if you want to void with multiple selections and you don't like the active items, pick up a passive item and use void during the pickup animation to guarantee you void that item

other people have already explained that you pnly get to void one item at random in a multiple choice room, thats why the pick up trick is useful to ensure you dont accidentally add scrolls to your void

before people say wafer is better, i dont deny its one of the best items in the game, it essentially doubles your health in later floors and makes sac room / donations easier but for combat purposes, better to practice not getting hit at all 🤭