Your root filesystem is NTFS? That’s likely the problem - I’m surprised it boots at all. Switching to a Linux filesystem is the likely solution. You could also try a newer kernel, too - 5.10 is quite old, current LTS is 6.1. Good luck.

Give each screen other than the “main” one a relative position - left-of or right-of, I think that should do it.

X11 is also just a protocol, and will live on with or without Xorg.

You’ll be fine as long as you maintain the system, don’t wait too long between updates, and pay attention to the output when you do. I’m running arch on everything - work laptop, a spare laptop, and a server (nas, Plex, home assistant, etc) - two of which are critical systems for me. I use ZFS for all storage pools, including root, and zfsbootmenu, so I can rollback to a previous snapshot if I ever need to or the system won’t boot.

It’s not really worth it, honestly. All netplan does is generate a config for systemd-networkd. It’s better to just configure systemd-networkd directly and have a portable configuration, rather than use Canonical’s proprietary stuff. The documentation is quite good for systemd in general, and with more people using it directly for network config it’s easier to find examples when you need help.

No, it’s a pointless exercise that makes no sense.

FreeCAD. It’ll do everything, but you have to put some time into understanding it. Fortunately, there’s are plenty of YouTube videos when you do get stuck.

Ah, I thought you were displaying on both outputs, not switching between them, hence my mirroring comment. I suspect XFCE, not the DM, detects the output change and takes care of it. You might need to emulate that behavior with a hook of some type that you have to setup yourself with the tiling WM, and you might have to --off the unused display. I’d be willing to bet you can find some sort of hook script out there that can do this, I seem to recall an autorandr program I used in the past where you could set up output profiles. I hope that helps, maybe a little bit.

Most major Linux distributions use systemd-resolved for DNS but there is no utility for changing its configuration.

Nor should there be. That’s what the configuration files are for, and the utility to edit them is the editor of your choice.

It’s just the same thing as man -k.

manpages. For many of us, it’s the only documentation that existed prior to the Internet.

I use i3-wm and just set my laptop display and external monitor to their native modes manually with xrandr. Been doing it this way for years without an issue. The only time I’ve seen the output get chopped like you mention is with mirroring, where you have to use the lowest common mode - but I don’t mirror, I set each display independently as a separate output for i3 (but on the same X DISPLAY).

I also don’t use a login manager, I login to a VTY and startx, old school but simple and reliable.

It depends on what you are doing, but there are lots of viable free alternatives. In addition to GIMP you mentioned, take a look at Darktable if you do photo editing. Any piece of complex software takes time to learn.