Help with radar chart using comma separated list in field

I have a field in my dataset that has a comma separate list in a field to tag rows. I want to create a radar chart where the values are unique values in the comma separated lists and the number of rows to include that value.

For example, if the column is “tags”
Row 1 | cat1,cat2,cat3
Row 2 | cat3,cat 4

The radar would be
cat1 = 1
cat2 = 1
cat3 = 2
cat4 = 1

You would need to do this in SQL. For instance in Athena you could make your tags into an array and then unnest it. Quicksight can’t create rows from columns.