It is a shame that so many ancient and beautiful rites have been discarded. I once read that the Church never drops anything ancient from the liturgy. This doesn’t seem to be the case.
I would try to contact others who feel the same way about the ancient Abrosian Rite. Maybe there are people who are fighting for the use of this liturgy; they may be able to answer any questions you have.
If enough people lobby for it, the Holy Father may issue a Motu Proprio specifically concerning this rite.
To answer your question, I don’t think the Motu Proprio concerns the ancient Ambrosian liturgy but I do think that it’s message is applicable to your situation. For example, the fact that it was never abbrogated, and that it is still a valid liturgy of the Church etc.