LTE not working despite coverage

We own a garmin bounce since november. Unfortunately, in the whole urban town we live as well as in the next 10km around us, the garmin bounce is not able to connect to LTE, and this despite very good 3G, 4G LTE and 5G coverage on all service providers. The map that garmin provides regarding network coverage also shows that the whole area we live in should have LTE coverage. When we drive further away then all of a sudden it has a LTE connection and the watch works perfectly fine. 

The garmin bounce has already been exchanged for a new one, problem stayed the same. I have been in touch with garmin support for several months now, the standard answer was that they are forwarding the information to the tech support. The latest firmware updates did not work on that issue.

Anyone else having the same problem?