OMG Why is Mail haunted/suck so much?

[Attirex]

1. I'm not sure what I did, but now every time I boot up my 2014 Mini running Big Sur, Mail stretches across both monitors in a weird way, and I have to manually resize it to one screen.

2. My inbox just disappeared.

3. Icons for what appear to be a grouping function just appeared next to relevant messages, and I can't seem to hide this column (ie, I don't want this grouping function).

Jesus h, Apple.

 

[MBAir2010]

mac minis are having problems with external monitors running big sur i read just know in MR twitter and macworld
there should be a patch or upgrade, we hope!

 

[Monotremata]

mac minis are having problems with external monitors running big sur i read just know in MR twitter and macworld
there should be a patch or upgrade, we hope!

No, the M1 Mac minis are having issues with their graphics (what choice does a Mac mini have other than using an 'external monitor'?), and the OP is running a 7 year old Intel model.

No clue whats up with Mail (it has bouts of possession by the devil here too) but it certainly has nothing to do with the display or its display drivers.