If I were you I'd insist on getting the car updated before anything. When you say the update gets stuck its actually not stuck but unpacking the huge firmware archive. You need to give it some time and preferablly keep it connected to a wifi so that after it unpacks part 1 it continues with downloading the rest of the parts.

We arrived in the nightmare when before using washing machine or a car you have to download software updates, restart it couple times.

I am mostly tech enthusiast but as a proper adult I want to scream "fu* off I just want to use that damn thing I want to play with my child and not watch another progress bar".

Also I am fully convinced that if you don't look at the progress bar something will ALWAYS break during the update so you never can just leave it to update on its own, when I look at progress bar it always works. But that's just me :)

He bought a car from another country, I believe he should have a couple of hours to try update it before calling it dead.