I have good news: very soon (probably this week), a Merge Request that drastically improve the deployment process when using docker will be merged.
As you may know, setting up the Nginx proxy that Funkwhale needs to work is usually the painful part, where mistakes are made, breaking the app completely.
Once the MR is done, we'll offer a dockerized version of the Nginx proxy, so you won't have to bother setting it up by hand :)