It seems that Mobifree largely depends on the Android/AOSP ecosystem, which is controlled by Big Tech.
So AOSP is a lot better than the alternatives, I would say.
I have a different feeling about Chromium: it is open source, but through it Google gets to control the future of the Web. But Android is not a standard, it's "just" one OS, so changes made by Google in AOSP don't really impact, say, iOS.
That's interesting because I personally do believe that Android is kind of the mobile standard, it has everything to be one, from the wide variety of devices to the certifications of conformity.