Not sure what you are referring to when you say limited or unlimited hotspot. Data is unlimited on hotspot but data speed is not. Speed on hotspot is capped at 5Mbps for the base plan and 10Mbps for the plus plan.
If your phone shows a 5G connection while hotspot is on versus 5GUW when hotspot is off I don't know what that issue would be. It could be since the hotspot is limited to 10Mbps on the plus plan it may not be fast or creating enough data demand to trigger UW. I am just guessing as I have read much about UW since I am in a 4G LTE area.
There isn't much traffic here so if you have a Reddit account try posting on the Visible Reddit page.
