iPhone 13 hot spot vs wifi

Home internet provider is down. WFH. My Tmobile plan includes hotspot. However Cox internet is down. Need to join my laptop to my iPhone for a meeting. Turned off wifi as my wifi has currently no Internet, Cox is down. If you don’t turn off the WiFi on the phone while Cox is down the iPhone won’t defer to the cellular data. The iPhone hotspot then comes with a pop up stating it needs the WiFi to connect the hotspot. Facepalm. If my WiFi had internet working I would not need to set up the hotspot to use my cellular data for which is included in my plan. iPhone was useless to connect. Fortunately I had O365 on my cell phone and could at least connect on the small screen. Why is Apple blocking the use of the hotspot on the cellular network when that is exactly the time you need it? If the WiFi and Cox internet was working I wouldn’t need the hot spot. I toggled on and off and rebooted the phone several times to no avail.