I’m not sure about using it without a Google account, but you can definitely minimize their involvement. I installed flauncher, then disabled the default “leanback” launcher. Plex is installed from the play store but I side loaded an ad-blocking YouTube app. On a normal day I don’t see anything from or about google on my screen. I’m not sophisticated or, to be honest, concerned enough to know if there’s tracking or other telemetry going on. I mostly just want to avoid ads and moronic suggestions from them.