I moved some posts to this new topic because time is running out. There are only 3 weeks left.
Unfortunately, there does not seem to be a (practicable) solution) for this yet.
My tutorial How to build a big app will then be out of date and no longer applicable (Nov 2021 at the latest).
I really hope that I will get a solution / idea for this, especially from @ewpatton and / or @Diego.