I am thinking about something similar to OneNote’s “take screen clipping” where you do a key combination (it used to be Win+Shift+S but Microsoft being Microsoft went and used the same for W10 built-in screenshot feature so you need to change the combination for onenote to something else via a registry key-doesn’t matter), you get the cross-hair, make your selection and you release the mouse it just goes to some note without you having to find the note, paste it there or anything. The workflow I have in Joplin is precisely the same, just Win+Shift+S, select with mouse and release, then bring Joplin to foreground, find a note somewhere in Joplin, go there and paste it (then go back to the original app).
The question is how to skip/automatize the last part? New feature? Would something with Autohokey work?