the.com/grandstand

means To show off or play to the audience instead of focusing on the actual task — making sure everyone's watching while you do it.

from From the grandstand itself — the big roofed structure at a racetrack or stadium where the well-off sat to watch, as opposed to the cheaper open bleachers. By the late 1800s, American sportswriters started using 'grandstand play' to mock athletes who showboated for that crowd instead of just playing the game — a hotdog catch, an unnecessary flourish. The noun became a verb for performing at anyone, anywhere, with an eye on the audience rather than the outcome.