We've noticed that Collector 20.1 and 20.2 have long submitting times to the point where it timesout. I've done some testing and it seems like point features and simple lines (2-3 vertices) submitted without an issue. But once you start to capture more complex lines with many vertices it timesout when submitting. However, yesterday I had trouble submitting just a point feature. I thought maybe it was the version so I moved from 20.1 to 20.2 without any luck. But if I revert back to Classic while using GNSS the features submit perfectly fine no matter the complexity.
We're using ArcGIS Online with enterprise logins on iOS 13.5.1. Trimble R2 units.