Derech: The merkava was just an example of chariots that don’t look like chariots. Maybe he did go up in the merkava, maybe he didn’t. The words ???? ?? imply that the chariot he went up in wasn’t the one from Yechezkel because the maaseh merkava doesn’t mention horses.
What matters is if the purpose of this vehicle was to bring Eliyahu to shamayim or to another planet. Without any mekor, for saying such a chidush, you need to bring a proof that it is anything other than what is commonly explained.
We’re agreed. Of course there is also the opinion that he actually died and all subsequent instances of gilui eliyahu were his neshama being used as a malach (Radak quoting someone earlier) in which case the chariot didn’t bring him up, he went up as all neshamos do.