About flicker ? Samsung is known to be the worst at PWM, eye strain on my a53. High amplitude 100mv) and low freq 250 Hz and also modulation ( not fully square wave) ,= big eye strain especially at night ( well, shouldn't look at phone at night either... For sure).
This (SD 888 one) or a54 ?
Exynos not as bad on my a53. It throttle a lot for sure and eats lot of battery but only if you push it, otherwise is good to me.
Sd888 is because I prefer the Sony camera.
Lightweight I appreciate a lot.
For lot of web and social media text and video call.
I tried many many midrange and returned to Samsung, price camera design software s usually well balanced. Except the bloatwares.
Also a21 fe has it many unremovable crapware ? Like those bloaty spyware forced updates battery and privacy and security leakers, Bixby , Knox and all... It should be possible to disable at least, bit usually no way.
Idle power is not great at all but 4500 and SD with 5g and lightweight, we can't have it all.