Most credit unions consider "new" vehicles as anything within a certain number of model years - for example through December last year my CU that I have for my auto loan considered a new vehicle to be 2021 and newer - even when 2023 was coming out. Actually, even looking at older car loans, they have held interest rates across them at the same rate.

Definitely do NOT use dealer financing unless it's an amazing deal. Go to local credit union and get preapproved for an auto loan. Don't say anything about the financing while looking at a vehicle, just sort of say thinking about financing, etc.. Then negotiate the price of the vehicle and say you'd like to use your own financing.