I have no VDSL experience, only cable service. My plan is 100 down, 10 up. I consistently get 115 and 10 on the NY test server which is some 500+ miles away.
Theres certainly no evidence in your test data where you’re getting near your 33 Mbps plan Max. I would continue to call your ISP on this. Be persistent but courteous. It may take several calls.