Maimonides’ rulings – according to the Jerusalem or the Babylonian?

It seems to me that these rules were invented before the discoveries of the twentieth century (and even a little earlier, in the Netziv's commentaries on the queries), which shed new light on the way the Maimonides studied the Babylonian - for example, the many teachings of the Ge'onim that were discovered, and the works of Rabbis Benedict, Kaffah, and Rabinowitz.
To my impression, in almost all cases the Maimonides does very well according to the Babylonian - if we only keep up to date with what has happened since the Netziv and onwards, and are not stuck in the time of the authors of the rules.
And what's more, the Maimonides himself, in the introduction to the Mishnah Torah, prefers the Babylonian.

Hello Uzia. I did not research the issue itself. My argument was that the authors of the rules also meant the rule that I wrote here and not that the Maimonides generally rules as Jerusalemite.

I understand that the neighborhood of the questioner is also yes to this. If the claim is really that the Rambam usually rules as a Jerusalemite, it is clear that there is no basis for this.
But even the owners of the rules who claimed that this is the case in a minority of places in order to settle difficult laws – it turns out that they were wrong. This is what they thought 400 years ago, not what we know today.
(In parentheses: It seems to me that understanding the Rambam's rulings is one of the only Torah fields, if not the only one, in which there is a phenomenon of theoretical obsolescence, as in the natural sciences).

A huge and interesting topic.
The Gra wrote in several places (in the glosses of the Shul) that the Maimonides' way is to lean towards the Yerushalmi.
The case I know of is the ruling that the Gra brings in Bikurim and reads, as the Yerushalmi ruling in Bikurim, against the Mishnah and the Babylonian Peshta following it.
The Gra Shaul Liberman has researched the subject extensively (in the book “Hilchot Yerushalmi for the Maimonides”) and has shown that the Maimonides did indeed often rule like the Yerushalmi.
Here is the book, which was discovered in the Cairo Genizah and, according to Liberman, was composed by the Maimonides:
https://www.otzar.org/wotzar/book.aspx?198458&