Hi! I am having the same problem.
I am using joplin-cli on Ubuntu 20.04.
I attempted to set the editor to vim after finding the absolute path
$ which vim
/usr/bin/vim
Using the command
:config editor /usr/bin/vim
And I can see it is succesfully set when I run
:config editor
Because joplin outputs
editor = /usr/bin/vim
But I get the error
Error opening note in editor: spawnSync /usr/bin/vim ENOENT
Whenever I try to open a note. This is replicated with nano (/usr/bin/nano) and vscode (/snap/bin/code).
I also cannot find how to reset the editor, so my app permanently breaks unless I remove and reinstall it.