I can see that you don’t want to make a plugin, because you don’t want to do maintenance.
There isn’t a v5 yet.
And I won’t accept a PR to the update plugin for a new editor feature, since it’s out of scope. (If it’s in core, I’ll have to adjust the update plugin to handle it, though.)
The problem with this - as I see it, at least - is that TinyMCE v4 is what is available to the whole ClassicPress community today. So by far the quickest path available to get this working and available to everyone is to make it work with v4.
Still, if you want to keep this working only on v5, then that’s fine. Please do post your code somewhere though, so that we can see how it works and someone else can pick it up for v4 if desired!
In the broader open-source community it is common to encourage people not to ask for deadlines, especially for smaller projects where everyone working on it is a volunteer and the scope of work required is not always well-defined. I think we should adopt that mindset and expectation with ClassicPress as well.
I’m testing tiny 5, enriched editor, tiny 4.9.11 and 2 of my plugins that add buttons to the editor on 2 sites (one production and one with the develop branch of CP). If you publish i can add it to my test.
Really I’m very bad with JS but I can try to help with tiny 4 compatibility.
I still have to work on attachments as @viktor proposed and copying the image directly from the “screenshot to clipboard tool”. Currently only works by directly copying the file from the system.
The positive side of merging this into the current research plugin is that I can work on this without interfering with the other tasks at all. But yeah if that’s not an option, I’ll keep it updated in the forked repo.