Depends on your age, assuming from your username born in 1993? Would say downtown if you can afford it, you get easy access to both burnaby and richmond to satisfy what you desire haha
If you rely on Chinese food, Richmond is the obvious choice, but Burnaby has a decent selection too.
Traffic wise it’s shit everywhere during rush hour, but downtown probably the worst. Driving is on average 30 min from city to city. If you’re commuting though, skytrain from Vancouver is more convenient to both Richmond and Burnaby as there’s no line from Burnaby to Richmond and vice versa.