Fancy brunch, lunch or dinner in Hanoi

Dear Hanoi community,

I am travelling with some friends of mine from Dubai to Vietnam. We will mostly backpack, but do not want to miss out to see also another facette of Vietnam, so we were thinking of doing brunch (will be there on a Friday though, so I am not sure if brunches are available), lunch or dinner in a fancy, fine dining place. We will be travelling to Ho Chi Min, Hoi Ann, Hue, Halong and Cat Ba, on budget but want to also see the upper class side of Vietnam in Hanoi. Do you have any recommendations?

Also, where is a good place in Vietnam to buy art (paintings)?

Many thanks in advance... Any feedback will be highly appreciated!
Greetings from Dubai
Angel