There is not going to be a EQE 63. In the US, I bet the EQE won't even have the number. The AMG EQS 53 will just be called "AMG EQS" here according to the latest info I have from MBUSA.
They may not use it, but it's trade marked by Daimler. As is EQE 43, 53, and 55.
The most important reason: we have Tesla and Lucid. Although BMW and Mercedes are acting like they don't exist. Taking the denomination from the pinacle of the ICE era will not turn their EVs into the pinacle of the new era. To put the '63' denomination and to keep its relevance the EV should be at least 1200 hp. But having less power than the base versions of the startups makes the use of the 63 moniker inappropriate.
I said without bias, and straight away you have to drag two other brands into it to emphasize your opinion that they're better than Mercedes and framing the naming around not what the
name is (or might be as Serpens reasonably points out), and not what the
product is, but what you think the
product should be - to me this simply looks like a way of sticking the boot into Mercedes because you think this...
... rather than a sound basis for a naming strategy.
I don't think any brand is going to name their hierarchy according to power levels relative to other
brands. Should the C205 C63 AMG hve been called the C32 AMG because Dodge launched a 700+ horsepower Challenger Hellcat? No, because that would be silly.
But that aside. For any given designation the power will likely climb, and if Mercedes want to introduce another model with a big step more power they can go beyond "63", as they have done in the past, with 65, 70 and 73 badges. "63" doesn't have to be the pinnacle.