Supposed that we are syncing multiple screenshots
Standard iOS sync flow: Open Photos -> Select Screenshots -> Tap action button -> Save to Sync -> Open Multitasking (Back to home screen)-> Switch to Sync
We have to manually do 6 steps.
Supposed that we have the required sync URL schemes and use workflow: Open Today widgets -> Use Workflow to select the latest screenshot -> Tap done -> Workflow automatically save to sync -> Workflow automatically switch to Sync
Now we have to do the first 3 steps and the remaining are done by Workflow.