It is not a question of whether it works, but whether you benefit. You have to look for relevant tests that show how high the maximum charging current is that your device can handle. In the case of the S21 Ultra, I charged at 37 watts, which is well above the 25 watts specified, and you can clearly see that in the comparison. The phone charges much faster than before!

I bought it for my galaxy s20ultra, I don't know exactly how many watts it charges with, but it charges very quickly in the mobile phone it says super fast charging. I have this in the living room e.g. quickly for 30min to charge the battery again about 60 %.

Yes