The car would probably be better if Apple made it themselves, completely.
You can see this with Volkswagen Group, where the cars aren't too bad but the software is...lacking (to use a nice word).
Mercedes OTOH actually has decent software (just the server-side is obviously useless, sometimes and even the EQS gui seems to be slow, which is ridiculous given the price-point), but the cars are "meh" from a pure EV POV. Don't get me wrong, the new EQS is a great car - but it's also way too expensive and way too large for Europe.
But if you look at Tesla (and some Asian manufacturers) - their cars are just way more efficient.
And especially in the case of Tesla, that is because they were designed to be EVs from the ground up.
Unfortunately, the way Tesla is run is not how Apple runs its business. At least not, since Steve has died.
And that doesn't even approach the elephant in the room: Musk's "online presence" and the constant stream of "leaks" that are only thinly coated Musk tweets that he can't personally tweet anymore for legal reasons.
Tim Cook couldn't stand that for five minutes.
Thus the idea of these two somehow cooperating is a pipedream IMO. Though there are of course some similarities in how they approach things - but that is hardly enough common ground.
E.g. I'm sure Apple is quite impressed how Tesla can keep their products under wrap until the last minute. Tesla is a tightly run ship.
Both Tesla and Apple are also way too big. They'd be consumed by just "merging" for years.
My car is 20 years old, but currently it looks as if the next one is a Tesla - precisely because it's not a Mercedes and my guess it I can keep a Tesla running for longer with less expensive repairs.
And with the Apple car, it's not even clear if you can purchase it or if you must lease it.