I've used Fire TVs for years, and have always used apps like Apps2Fire and Easy Fire Tools to easily transfer and install APKs downloaded on my phone to my FTV devices. I was searching for a similar app for Google TV, but every search for how to sideload on Chromecast/GTV just shows the cloud drive or USB + file manger method. Is there no phone app that makes this easier, and not require a file manager to be installed?
Easy Fire Tools works with CCwGTV. I just need to enable USB debugging within Developer Options.