I don’t like dual monitors either, but at my desk I basically just ignore the MBP screen and use it like I’m on a desktop with a single display. (I don’t close the lid for thermal reason, but I imagine I wouldn’t worry about that once I’m on an ARM Mac.)
I also find it a source of distraction in that the other monitor that I’m not currently working on disperses bright lights out of the corner of my eyes constantly vying for my attention
The Apple XDR 6k is nice but isn't compatible in a PC+Macbook setup as it only has a USB-C input. No ability to connect a PC if you're already using the USB-C for a MacBook.