Looks like a nicely made app indeed !
Unfortunately I wouldn’t have any use for it, and I really don’t have any time right now (and I’m still a very beginner packager). However, I had a quick look :
- The software is meant to be installed with Docker or Docker compose, which is usually not a very good sign (as Yunohost is not recommending using docker for app installation).
- However it looks like a nodejs based app, and you can always have a Yunohost install script performing the steps as described in the dockerfile
This is exactly the same case as for my first app, for wich I managed to get rid of docker and start a clean Yunohost setup (with the big help of professionals out there 
, and still needs a lot of polish of course). You can also look at the Peertube app, which I used as a reference of nodejs 14 based app installation when I did my first trials packaging Outline.
If you have a minimum of technical knowledge, starting packaging is surprisingly easy and you may get a lot of help here when starting building something ! Good luck !