We are already working with the solution provider (not the brand and not the factory) to make an Android 10 firmware for the DM20 (MTK M6739 version)
It works like this:
Factory designs a new model.
Brand orders how many they want (other brands may also order) and have their name put on them.
Solutions Provider is a separate company that builds the user solution based on the factory and brand requirements.
Shortly there will be an SPRD Unisoc version of the DM20… Also 3+32gb or 1+16gb.
The S21 model is a similar unisoc powered model but there is also a Unisoc DM20 on the way.
This is because MTK prices have gone up.
However, there is still some M6739 DM20 coming.
So we have joined with the solution provider again to make this M6739 version work with Android 10 and, as an International model, much like the ones that we have worked on already.
A more AOSP + Google based solution.
But only for the MTK model.
Answer to your question:
With magisk and magisk manager installed and the correct busy box installed as well - you should be ok.
It is strongly advised that you have twrp as well.
As long as you have these things you should be able to fix the encryption problem.
A word of warning though.
If you actually sold this model with your own firmware installed - DMN (Domino) will come after you for breaking the copyright they have on this design and board.
Not Lemfo, but the actual owner of the original DM20 design - Domino.
The original design is often referred to in China as the “mold”
So it would be much easier and safer for you to wait a little longer for the official release.
In the meantime you can play around with your own device without problem.
In my opinion.