sombra’s issue doesnt lie with the support or even dps. the real problem with sombra occurs when mentioning tanks. what makes ow harder for tanks is the issue of CC that slowly started creeping into the game brigitte and doofist are the killer in that departments. however sombra with her hack can make it it 10 times worse that dealing with CC as unlike with CC, hacking takes away the ability to even to do the job of providing space.
In Solo Q or better lower elos this might not seem hard or an issue but if you start to claim such issue will and are much better punished by the opponent if they cant do their jobs in a comp.
now if a certain parts of a comp cant do their job or are useless why run it. All this is something a good and buffed sombra could do with either a winston or rheinhardt,