The worst merry-go-rounds weren’t the metal ones, they were the ones made of wood with just the bars made of metal. You’d slide on those and end up with wood slivers stuck in your legs and backside, cuz they only repainted them once a decade.
My mother spoke of those - she said there was one at her elementary school and she used to get splinters all the time.
The metal merry-go-rounds we played on heated up in the Central California summer to lethal degrees (daily temps of 110 are not uncommon there).
We played on it anyway, sometimes melting the bottoms of our shoes.