@Irena Great to hear. The issue with Google Ads Support is that they do not do a deep dive. Generally, Google Ads is a self serve platform. Which means, you as a user, need to figure it out yourself.
Sad, but the reality. That is why there is so much demand for specialists to assist.
The issue was then indeed what I thought it was. IE subdivisions, when you subdivide using product type, and you change these values it will remove all products if the values no longer match.
In any case, glad you resolved it! Great work.