Xfinity Mobile’s bring-your-own-device program is fairly restrictive. As of June 2020, the program allows some iPhones, Samsung Galaxy phones, and Google Pixel phones. I’ve seen indications that Xfinity Mobile intends to expand its bring-your-own-device options, but the carrier has not been adding more supported phones all that quickly. You can check whether a specific phone is compatible with Xfinity Mobile on the carrier’s website.
As far as I know, Xfinity Mobile has not set a date for when it plans to allow all Verizon-compatible Android phones to use the service. It’s possible the carrier has no intention of doing that at any point in time.