There's a reason you can buy a large high-quality smart television for just a few hundred dollars. Smart TVs are terrible privacy invaders. They monitor and monetize everything you do. It's much more secure to simply turn off the wifi on the TV so it cannot phone home and use your own AppleTV to provide the content you want.
I find Apple TV streaming picture quality is superior (over my TV) when choosing higher format resolution options available in the latest Apple TV 4K, especially in upscaling HD content.