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.