I have streamlined and automized my entire process with a Python program I made.
It allows me to select a video, select the corresponding song from Spotify, select certain parts that have to be cut off (such as intros and outros) and then it will automatically download the video, transcode it, cut off any segments, merge the metadata.
Before you set up Collabora, you should know that the rendering is done server-side and not client-side.
This provides really good synchronization, as the clients will receive the changes simultaneously, but it also results into slower performance, because the server has to do the rendering, instead of the clients.
The problem with OnlyOffice is that it doesn't allow for editing from Android, because then you'll have to pay, which is why I switched to Collabora Office.
Thank you for your comment.
What do you mean with the http layer? I'm already automatically redirecting from HTTP to HTTPS.