I have the same issue – but with list-to-list searches on many-to-many relationships. Like… does this list of things (in a list field) contain the items in this other list of things (items selected by a searcher). An example is… does this blog’s tags contain the tags the user has selected in search constraints.
My plan is to create a 1:1 joining table to get around this and then experiment with the most performant way of integrating the joining table search with regular searches on the datatype (since users will be putting in multiple types of search constraints).
Note though that I haven’t needed advanced filters for 1-to-many searches like you describe (I run them server side via the regular “search for” box), so maybe I’m not understanding your example.
PS: I think advanced filters should come with a big warning in the editor that “this isn’t scalable, so your app will slow down as the database grows”. Advanced filters have some needed functionality, but it’s a band-aid approach and ideally Bubble does some development that allows us to do more types of searches server side.