I’m not convinced that a beginner understanding that masu form etymology coming from mawirasu and seeing it as two words makes Japanese grammar easier to understand. In fact, very few may find it actually useful at all. I’d rather say it ‘conjugates’, and move forward though knowings it’s more conceptual for foreign language learning. Knowing the history of cars or skills of engine repair have very little to do with actual driving ability. It’s not to say it isn’t interesting. I like it in fact, at least to the point of functional linguistics for enchanced language study but not for the sake of it (my language journey is very much a part time gig, for others I can see the appeal if you have the background or pursuit).
I came across this book while responding here, seems there is quite alot of grammar-verb theory within native material though whether it covers this specific topic, IDK but the title seemed interesting (paradoxically, you need to learn Japanese grammar with its ‘conjugations’ to find out )