Question about Dell P2421DC

Dell consider this screen to be flicker-free but it is not fully pwm free though which should not be noticeable

Yes, and is currently offered by me for 200.-. Warranty until August 2025.

Yes, of course, LCD screens flicker like earlier cathode ray tube screens, because the picture composition is completely different. The refresh rate of this model is 60 Hz, which is not perceived as flickering.