Rotation in a 152 should be 50 knots, but 60 will be okay.
Rotation in a 172 should be 55 knots, again a little faster will be okay.
Either of them should be ready to fly at those speeds and all you need to do is add a little back pressure (pull the stick aft) and hold it there until the plane rotates and comes off the ground. If you do this at a faster airspeed, it will more firmly rotate (called an “unstick”). The faster you go, the more effective your controls are and the more responsive the airplane will be.
What the sim isn’t replicating is force - in real life it’s not easy to just yank the controls to their stops - the airflow over the control surfaces (ailerons, elevator, rudder, etc) will “fight” against your inputs (again, moreso at higher speeds). Our various joysticks, yokes, and game controllers use springs to replicate this, but it’s still too easy to go to the stops and overcontrol.
So what I’m guessing is that you have a combination of speed and overcontrol that’s making it difficult. As to why the two planes are behaving so differently (they really shouldn’t - the 152 is lighter and more nimble, but doesn’t have as much power), I can’t answer that. Maybe there’s a flight model issue? Have you checked to make sure your flight model is set to modern (not legacy)?
Flaps up for takeoff unless you’re doing a short or soft-field takeoff, then use 10°.
Trim deserves an entire thread on its own. Why we use it is to relieve control pressure used to maintain a certain attitude. It’s affected by pitch/power, weight/balance, configuration and aircraft performance.
The details as to what and how it’s correctly used is a little more detailed - it’s not lesson one material. Simply put - set the nose where you want it with the elevator, then use trim until you don’t have to use any pressure on the elevator. Takeoff trim should be set so the the indicator carat is aligned with the line next to the trim wheel.