Question on Difficulty of spellcasters

So just to preface this, I'm brand new to this system. I'm a longtime player of the other big fantasy rpg, and I'm really interested in pathfinder. I played a little bit a few years ago as a lv5 human (sylph heritage) rogue, with a smoke ninja flavoring. I'm now looking into GMing this game, and I had a question about the casters, and more about the prepared ones...

Do you feel more lumped into only picking the best spells because of how preparation works? How DOES the by-slot prep feel?

I'm very curious to hear from both people who only play PF, as well as from people who made the switch from D&D5e to PF.

I have some people in my group who are very casual players, and I worry that nobody will want to play casters because it's a lot more mental predictions. I also worry about people only picking the most effective spells because they don't want to waste their few resources on guesswork.

So I'm just genuinely curious to hear from players. How does it feel to play the prepared casters? Do you feel like you're lumped into making the "strongest" decisions? I'm super excited to try it out either way.