Have you already tried connecting to the mobile hotspot with another device?
yes.
Is the behavior still the same?
No, the signal is weaker, and the connection randomly disappears from my phone's list of networks. My phone randomly loses connection at times, and I can't find the network. Sometimes, windows still claims that my phone is still connected although my phone is not.
When the hotspot network appears in the list of available networks, are the WiFi signal bars at maximum?
When I don't have the antenna connected, no. With antenna, it's max. Without, only 2 out of 4 bars.
What bandwidth is configured in the mobile hotspot settings? If you prefer, post the screenshot.
I have it configured to 5GHz band.