Be very careful..I wouldnt update to Andriod 12 on your Chrome Cast/Google TV, as it can cause a bug where you lose the Unknown Sources. This happened to me and others. Offical Google supports thread can be found in the link..it mark solved but is not and main Support in the thread knows it and the issue is being looked at with escalation.
https://www.googlenestcommunity.com/t5/Chromecast/ChromecastHD-unknown-sources/td-p/246115
https://www.googlenestcommunity.com/t5/Chromecast/ChromecastHD-unknown-sources/td-p/246115