While the ability to tear off panes into their own windows (like Chrome or JetBrains) would be ideal, I’m very happy to find the symlink workaround, it’s working for me now, as the main thing I wanted was to be able to have another window open on a separate monitor.
I can report on Windows, that after experimenting with shortcuts, and file and directory “soft links”, the approach that worked was using
mklink /J to create a “directory junction”, which is the directory version of a “hard link” on windows. So for each new window I want, I need an extra uniquely-named junction/link somewhere (I just put them in the same parent directory that contains my vault). Not so bad; definitely better than having to nest it in 4 dirs deep.
I also use multiple monitors, that are different sizes and orientations and positions, so simply stretching the window across them, while better than nothing, is far inferior.
Basically I just wanted an extra window or two for my other monitors, and this workaround gives me the ability to do that, so for now I am happy. (There may be some weirdness or drawbacks to discover later with the shared .obsidian dir/cache, we’ll see.)
Thank you to all
(Update: after using this solution for several months, I haven’t really run into any problems or weirdness. I use Dropbox with and without Cryptomator to store and sync my vaults (one encrypted, one not), and access them from both Windows and Mac OS, as well as the unencrypted one on iOS using Editorial and 1Writer (which have built-in Dropbox support) and occasionally on Android via Markor and Dropsync (less convenient as Dropsync can be slow, but still works fine.)