I don't think we're going to get a "red" phone. Seems more likely that we'll just see people get Parler on Android through channels other than the Play Store.
>What then?
There's a lot of additional attack vectors. We've already seen Amazon move to boot Parler off its web infrastructure. If that fails to kill the platform, we'll likely see attacks on anything related to its financing, or things like CloudFlare protection. If that fails I could see progressives abandoning net neutrality to lean on ISPs to block traffic.
In reality I don't think we'll get all the way there, but we'll get close enough that a stable "red social media" ecosystem will emerge that's out of reach of cancellation. In the long run this may work out worse for everyone.