PostgreSQL how to merge rows where some fields match and others are null

I have some data that looks like the below:

I need it to look like this:

Is this kind of filtering possible in postgresql?

I’ve seen some answers suggesting to use group by to aggregate rows together but I don’t think that would work in this case, because I only want to combine rows where the categories and/or subcategories match. If I used group by category, sub_category then the result would be like the below, right?

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