TimNiceBut

I think the main mistake was to try and finance a car at a dealer. Try talking to a local bank or credit union for decent financing with fewer shenanigans, then go to the dealer - they might well try to beat the deal you can get but at least you have a baseline to work off.

When we bought our last car that's exactly what I did, but ended up financing the car at the dealer anyway as they were willing to offer me the manufacturer's subsidised 0% APR deal.