Question about Xiaomi Poco X3

Hello all I have had the Poco X3 for over half a year and am actually very satisfied with it. Now, for a week and also after the new installation, the hotspot is haunting me. On the laptop it conectet but no internet available, now and then it works and then it kicks me out again. Before the installation, I couldn't log into the Smart TV at all. (Message: Access point not found) Now it works again but with interruptions and it kicks me out of the network. (The TV was also set to factory settings before the mobile phone) I don't have a limit. Can it really be due to the mobile phone, are apps possibly a disruptive factor or is there even a barrier pushed by the network operator? (I have a flat rate) If anyone knows anything about this, I would be very grateful. :-)