Since less than 10% of Spanish speakers are from Spain, there’s no reason to assume you were specifically talking about that one country when referring to the Spanish language in general.
And anyway, as you point out, even in Spain the form México is accepted now.
I thought it is perfectly reasonable to talk about spanish from Spsin the same you talk about English from England.
After all, it is where they come from originally and have their own spelling (colour vs color, etc.)
An x in standard spanish has always been the two sounds I told you and that mexican deviation is specific to Mexico.
Yes, it is over 100 million speakers but I was still assuming the root language in its original place as the reference. Sorry if I did not express it correctly.
I get your point, but FWIW, México is not a Mexican deviation; it's just an older Spanish spelling. E.g. Jiménez was once spelled Ximénez and there are probably lots of other examples.
The "root language spoken in its original place" absolutely did pronounce X like modern J.
And anyway, as you point out, even in Spain the form México is accepted now.