I used the Kohler Caxton sink in every bathroom in my build and it didn't matter how large or small the vanity was. We don't do anything more than wash hands and face in the bathroom sinks, so that size works fine.

Click to see dimensions.

20" IMO counter more important than sink.

Sink depth is what’s important for me. Once had a too shallow sink, more water splashing onto the counter, also I dislike vessel sinks which seemed popular awile ago.

I agree with Lyn. 24” sink is plenty. We used this sink in a 60” vanity

https://overlandremodeling.com/bathrooms-gallery/modern-bathroom-design-simi-valley-ca

Vessel sinks are great for powder rooms. They’re not practical in my opinion for primary bathrooms.

I also used Kohler Caxton sinks for my bathroom renovations (four sinks - two for primary bath + one in each upstairs guest bathroom). They're a good size.