After driving a 20+ year old Camry with 350k miles that still ran great, I finally convinced my dad to upgrade. We got a 2025 Santa Fe Calligraphy. It’s beautiful and we really want to just enjoy it for years.
We went on vacation for just 2 weeks and left it in the garage. When we returned, it wouldn’t start. AAA jumped it, but after turning it off and trying to restart, we got nothing but an error screen - with under 1k miles on the odometer. AAA said the battery was bad.
We had it towed to the Hyundai dealership. After running tests over 5 days, they said some “modules” were taking over an hour to load but couldn’t pinpoint the actual problem. They didn’t replace the battery or fix anything concrete. When we got it back, there was black residue all over the steering wheel, horn, and door panel that we had to clean ourselves.
Now we’re dealing with multiple software issues: Seatbelt warning light stays on for all seats even when everyone is buckled (goes away after 3 minutes). “User authentication failed” warning never goes away. 
The dealership claims it’s the fingerprint reader (which actually works fine) and wants to replace it. From what I’ve read online, these issues can occur during battery replacement and just need a software reset.
Has anyone else experienced similar issues with a new Santa Fe? Can I easily reset or should I try the dealer again?

New 25 calligraphy died in the garage after 2 weeks with less than 1k miles