Is there a rule as to which printer will work? Mine is a Brother laser printer.Depending on your printer it can find it over your network.
You can set your brightness on low when you connect to a monitor, but you can not turn it off.
No, just on external monitor. Yes the ultrawide issue hasnt been adressed yet, but hope is alive now that iPadOS 18 is knocking at the WWDC door in a week.