I guess one of my contrarian takes here, is I don't really care about the tech side.
If CloudFlare hurts reliability overall (a big if), the best judges of that are their customers. CloudFlare does not have very strong lock-in, I think the market can handle this one.
I am much more worried about the non-technical failure modes that come with this centralization. The centralization of power, the inevitable? enshittification that is yet to come. The risk that this MITM becomes hostile.