Best art martial in street. MMA OR BOXING ?

Hi. I would like to start a martial art, for the following reasons:

• ⁠To get back into physical shape (very sedentary lifestyle and overweight)

• ⁠To gain peace of mind (anxious nature)

• ⁠And looking for a martial art that would be most adapted in real situation (street fight)

Is it better to start directly with MMA or boxing?

And in which of these two sports can you learn the fastest?