Create a view to list all contents that uses media through any entity reference field
Mostly yes, by adding relationships to a view. The drawback is that is not done automatically: you manually have to add all entities/fields that possibly can refenrence a media entity. Create a view showing media entities. Then add the related tables and filter criterias "related/foreign field referencing media -- is not empty"

I'd not recommend the "File usage" relation and its "Use count" field. It doesn't seem to count correctly in my projects.