I have an SM-G998U Ultra 5G and fortunately no issues charging. I bought an aftermarket wireless charger and every other night I lay it down with between 10 & 20%, and have full charge by morning.
My S21 Ultra is taking 1.5 hours to charge from 5-100% with the Samsung 25W super fast charger and the cable supplied with the S21 Ultra.
And I have fast charging and super fast charging enabled on my device.
Any idea what I may be doing wrong?
I just had the same problem. Samsung ultra S21 from 2021 the charger does not come with the phone. I purchased a cheap charger, it took 10 hours. I went to Samsung site and purchased the original for $29 it just arrived. The charger is now superfast. Samsung have designed it this way.