I've been using an AppleTV as the primary way to get content to my (dumb, vintage 2007) TV for approximately a decade now.

While my usage has increasingly shifted toward drawing from my personal library through first Plex, then Jellyfin, I've also used Netflix, YouTube, Twitch, Amazon Prime Video, AppleTV+, and probably a couple of other content apps I'm forgetting on it. Aside from some issues with the UI of individual apps (which is, of course, on the developers), it all works great. Many of the apps can even show you a couple of tiles of "suggested content" right from the home screen (for instance, when I select the Netflix app, but before I launch it, it currently shows the next episodes from the most recent two shows I've been watching on it).

There are various ways in which an AppleTV can be better if you're already in the Apple ecosystem (which I am), but you absolutely do not need to be to make excellent use of it.

It can even join your Tailscale network and act as an exit node, giving you a quick & dirty VPN into your home network!