Google has announced the launch of their new project called Stadia Makers. It is aimed at independent developers who work on Unity engine (starting with 2019.3 version) and plan on releasing games in 2020 or 2021.
Slowly, yet daily steadilly Google does increase the number of Stadia subscribers. Now Google offers three free months of Stadia Pro with Chromecast Ultra. The best part is that you do not need to buy a new device.