I think what you listed matches with what he suggested, they just have words instead of a letter for the variants. Which is actually better in this example because the "Slim", "Pro" and "Digital" mean what you would expect them to mean here, versus the "a" in "Pixel 9a" in somewhat obtuse.

Dell is messing this up badly even though they almost got the strategy, "Dell Pro 14 Premium" is a real product and "Dell Pro Max 14 Plus" is also a real product, there's no way anyone knows what that means.