Funnily enough, M87* is bigger than Sgr A* by about the same factor than it is farther away (~2000x ?), and these effects mostly cancel out so the effective res

Funnily enough, M87* is bigger than Sgr A* by about the same factor than it is farther away (~2000x ?), and these effects mostly cancel out so the effective resolution of each is about the same. They chose to image M87* first because there is less dust/gas obstructing the view through intergalactic space to M87 than through the bulk of the milky way disk.