According to a report by MacRumors, “Apple has acknowledged that some iOS 13 or iPadOS 13 users may experience issues with Personal Hotspot.” The MacRumors gets this update from an internal document distributed to Apple Authorized Service Providers this week.
According to Apple, the Authorized Service Providers should expect some customers with complaints related to Personal HotSpot connection. The customers may also experience frequent disconnection from the HotSpot. The customers may also have issues with data performance while using iOS 13 or iPadOS 13 devices.

According to Apple, many users already reported issues with the Personal Hotspot as far back as iOS 13.1.2. Apple has been trying to fix the issue, but it seems it is still not resolved.
The service provider offers a temporary solution to turn off the hotspot and then turn it back on. It works for now. But Apple has to work in the future updates of the O.S. and fix the issue. There is iOS 13.4, but it is not clear if it will solve this problem or not.
Also, the latest Golden Master release notes do not offer anything on this bug fix. As of now, Apple recommends that the customers keep their devices up to date as it is not a hardware issue.