Copy and paste-able dependent dropdown list

I have two different setup sheets. First one is a table for my category and my subcategory. Second sheet is basically the same with different input, so not same (sub-)category. On my 3rd sheet i want to have different dependent dropdown lists.

E.g. sheet3: 1st row, left cell: dropdown category (sheet1), right cell: dropdown subcategory (sheet1)

2nd row, left cell: dropdown category (sheet2), right cell: Dropdown subcategory (sheet2)

Both subcategories should change individually depending on what I selected in their respective left cell.

After that I want them to be copy and paste-able in sheet3 while still having fully functional dropdown menus.

Some help would be highly appreciated. Nothing I tried so far has worked.

edit: my current solution that only works when I don't c&p is to have the first cells on sheet3 as the headers (categories) of the tables as data validation list and the 2nd cell as a formula like this for sheet1:
=SORT(UNIQUE(TOCOL(XLOOKUP(Sheet3!Cell1a;Sheet1Categories;Sheet1Subcategories;;0;);1;)))

and sheet2:
=UNIQUE(TOCOL(XLOOKUP(Sheet3!Cell1b;Sheet2Categories;Sheet2Subcategories;;0;);1;))

I have these on another sheet because I didn't manage to do it on sheet3. Problem is that it still references Cell1a/b if a move it around instead of dynamically changing it.