Well, fortunately Pix is statedriven/stateenforced/strateregulated, so it contains some of the most important ingredients to become some type of standard - the only reason why Mastercard et.al. are so powerful is because this area/field of tech was long no recognised as critical/relevant enough.
Pix is doing exactly the right thing, as ECB/SEPA is as well.
Totally, and hopefully if standardisation isn't possible that we will at least see some form of integration between these systems, even if under an international transaction fee.