Go to Settings>System>Notifications and turn Notifications off.
I must say I find Notifications useful but that's how to switch them off if you want to.
Have you tried right-click on desktop then select 'Personalise' from the drop-down menu followed by 'Background'. From this screen you should be able to select another background photo by browsing.
Yes, it cuts out the glass door element but it is still Wi-Fi and may still suffer from dropouts due to other things. Neighbour's Wi-Fi interference as well as router and TV's handling of the Wi-Fi signal.
Thanks for the suggestion though. It is not something I had considered.
I carried out a...
It doesn't seem to be but then I do not use my phone for streaming over a 1 to 2 hour period like I do with TV.
My phone has the 'WiFi Heatmap' app and that shows a strong signal -52dBm and a link speed of 390 Mbps at the TV location but I wouldn't know if this would be maintained over a 1 to 2...
I have a Plusnet Hub Two router and the Wi-Fi connection to my TV is generally good. I see dropouts (because it affects my on-demand viewing) perhaps once every 10 to 14 days. Dropouts probably happen more than this but unless I am watching on-demand content on TV I don't see them.
The TV is...
I don't have a fix but have you considered disabling Bitlocker?
Some people have Bitlocker enabled out of habit but don't really need it.
It may not fix the issue this time but it would remove one possible complication in any future issues.
Good luck.
Have you tried selecting the 'Light' colour theme in Thunderbird in order to contrast with Windows 'Dark' theme?
Thunderbird>Options>General
Left hand side, bottom-left click on 'Add-ons and Themes' and select the 'Light' theme.
@BamaInArk is correct in that the icon will only show if the app is running in the background so maybe it got stopped from running at startup somehow. Same with qBittorrent.