Sombra lost any semblance of being an off-healer when her rework fundamentally changed her playstyle.
What differentiated Sombra from Soldier back then was that healers benefited from healing their teammates. The first thing Sombra does at the start of a match is to hack the healthpack at her teams side of the map, and try to get her team to use them whenever possible. Soldier’s healing is only used for himself to give him sustainability during a fight, it’s not meant for his teammates.
That changed when Sombra got reworked. Not only did Sombra lose the reason to hack healthpacks for her team, using them would actually STEAL ult charge from the healers.
Like Soldier, her healthpacks are now only meant for herself and to deny the enemy. The first healthpack she hacks is now on the enemy’s side of the map to give herself sustainability while attacking. Using Sombra as a support now is fatally deterimental to your team as your side loses out on ult economy.