It depends on the specific model, but Ubuntu Touch will run on some Pixel phones and at least used to support running Android apps using Anbox or Waydroid.

The biggest problem with it is that VoLTE is not supported yet on Qualcomm chipset phones (of which the Pixel is one). The developers are definitely working on that, but they a very small team of volunteers so they can only move so fast. For now that means Ubuntu touch phones in some markets, such as the USA and India, cannot make or receive calls on the mobile network.

Mobile data works though so there are workarounds using VoIP or services such as Telegram or Signal if you’re wanting voice capability.

postmarketos apparently runs well on the pixel 3a, I don’t think the others are that well supported (or supported at all)