@luana@wetdry.world It will fully support using other operating systems including users making their own builds of GrapheneOS. It's part of our hardware requirements. We'll likely be able to make hardened builds of firmware and drivers which can be released in an official way for easy builds without needing to extract anything from the GrapheneOS or Motorola OS factory images.
Makes little difference now since Xperia abandoned the US entirely – but the last few years they were in the US, Xperia US devices were locked down.