I do have a solution as currently I do not see any aftermarket hitch manufacturer with a solution for your 2021 Cadillac CT5. You may be able to have a custom fabricated hitch made at a local welding shop. We have the Curt Weld-On 2" Receiver # E17 which they can use to fabricate a receiver for you.
The ZCI Circuit Protected Vehicle Wiring Harness # 119250KIT will allow you to add a 4-way flat connector to your CT5. This uses sensors which clamp over the tail light wiring to sense when... view full answer...