It seems that there is something about wildcard queries that it is not clear to me
As far as I understand, Wildcard queries are term queries so. the search term is not analysed itself and it is "compared" against the terms in the inverted index.
So suppose that I define an index using the default mappings and I put this document
"test_test": "I dream of butterflies instead"
and run a wildcard query (I'm just testing the behavior, I know that it is not a good practice to put a * at the front of the search term)
If you are using the default mapping the analyzed field is lowercased, which explains the case insensitivity in your queries. If you queries test_test.keyword you would probably get a different result.