I hear your pain. All new vehicles are full of electronics. They work great (generally) when new and for a time after that. When electronics get flaky they get real expensive. Add to that ...Salt exposure will eventually reek havoc on most electronics given enough time/exposure. Yeah it's a pain...I hear ya.
I would ask your shop to 1) ensure the grounds are top notch. Even those hidden grounds I mentioned. 2) Inspect the relays & fuses and ensure they're good. 3) Then Rule out the WIN module ...which is the module behind the key, a common source of start problems ..is good. Then 4) I'd probably inspect the TIPM connectors to verify are good, or possible corrosion. 5) Ensure the fuel pump is working. There's a cheap fuel pump relay bypass for like $12. But with your dash lights not working, that sort of makes me think it's not the fuel pump relay. 6) Of course verify the starter is good.
Honestly hardly any shops are going to want to do WIN module repairs, and the wiring is something a lot of shops will be befuddled with.
Find a guy who's REAL good with wiring & electronics, or they might be hunting all over the place and throwing expensive parts at it. Could get real expensive if it becomes a guessing game. That's exactly what you want to avoid. Buy a one-way ticket to Atlanta (or FL) this winter with some cash in hand, enjoy some sun & get yourself a rust-free (simpler) pickup. Then rust-proof the heck out of it.
Good luck. Circle back, Let us know what it turns out to be so we can all continue to learn.