Keep in mind that if a phone is rated at 50W, that’s comparable to a car’s top speed. It doesn’t mean the phone is charging at 50W from 0% to 100% continuously, rather it only reaches that peak for a fraction of the time here and there, usually between 0% and ~30%. After that, it slows down dramatically to keep thermals in check, because high battery temperatures will permanently degrade its capacity (AKA damage it). All phones work like that, from all OEMs (same with laptops).
My Phone (3a) is rated at 50W. With any charger I use - usually an Anker 736 100W (or 80W if something else is connected to one of the other ports) - it reaches 50W for maybe 2-3 minutes total, and always when the battery is under 30%. I measured this directly at the wall with this power meter, with nothing else plugged in but the charger and the phone:
So, tl; dr - just as a car capable of reaching 300 km/h doesn’t drive at 300 km/h all the time, a phone capable of charging at 50W won’t charge at 50W all the time.
