Their rebranding didn't really effect anything beyond the holding company. Facebook is still called Facebook, and the Google Pixel is still made by Google. I bet the general public has pretty much zero familiarity with the Meta / Alphabet brands.
In essence it was nothing more than an attempt to misdirect public attention away from their well-known brands. See, it's Alphabet doing a bad thing - they are totally different from Google!
So it should be MANA.