Rumba is characterized by slow dance rhythm and lingering and elegant dance style. Although its rhythm is slow, it needs muscle strength to express it. Although it belongs to one of the Latin dances of sports dance, it is still a dance in the final analysis.
There are many kinds of yoga, and fitness is very good for people's health.
It depends on what you mainly do, or just want to keep fit. I think yoga is very good.
But if you want something else, dance.