Faulty gearbox and electronic systems? That's a lot for a new car! And if they 'fixed' it but it's still happening, they clearly didn't. Have you thought about getting a second opinion from another mechanic or even a different dealership? Could be a bigger issue they're missing.
Missing accessories and a buggy infotainment system, talk about a plot twist for your new car! Hopefully, the dealer can work out the kinks and get everything running smoothly soon.