Data Validation list of comma separated values in a cell

Hi All,

I have a large volume of Products and their associated Models, which I am trying to produce in a spreadsheet with Drop Down Selection Lists for Each Product.
Once the Product is selected, I want to dynamically compile a list of associated Models from the product. Then pass that information to a Data Validation List for people to select the model from via the Drop Down.

I can get the data via a TextJoin function in a cell as a comma separated list as (A,B,C), however using the Data Validation List function, only one line is returned (A,B,C) instead of offering a choice of A or B or C.

I could perform this via a Dynamic Drop Down list as I have done in other spreadsheets. however this is too just too large to perform this way as there are 13,000 products and 70,000 models.

The lists are updated regularly.

I cannot use VBA as VBA is corporately locked out for users, I can only use Excel formulas and functionality.

I have attached a example of what I'm trying to achieve.
Is there anyway to achieve this?