Thanks for your feedback! We’re reviewing your suggestion.kaz commented
I'm suffering from this problem.
This is quite an old problem. I'm surprised by the fact that it has not been fixed yet.
MathType showed a temporary solution (https://dessci.com/en/support/mathtype/tsn/tsn150.htm). However, even after doing that, Word automatically changes the sizes of equations objects again, which is really annoying.