I use a dual monitor system with my LG Nano TV connected via HDMI as a second monitor and My Dell Vostro 5940 as my primary monitor. I have the laptop set as my primary monitor and the LG as 2nd monitor in settings. I have it also set to only show on the primary monitor. Every time when I start up my laptop the taskbar switches from the laptop to the 2nd monitor even when that monitor is switched off. Settings still shows the laptop as monitor 1 and the LG as monitor 2, so it is not swapping the monitors as such, but the taskbar is moved to monitor 2. The only way to fix it is by going into settings and duplicating the monitors and then extending them again. IF I set it to show on both monitors then the WIFI/Sound Icon etc all move to the second monitor. This does not happen if I reboot the laptop, only when starting it up for the first time.
The laptop is a dell vostro 5940 i5 10th gen with 16gb ram running windows 10 pro 20H2