I have been on Arch a few years now. I switched before the installer was a thing because I wanted to learn more about building my own system. Got hooked and still using it as a daily driver. I normally have to reinstall every 6 months or so. Usually my issues are all self inflicted. I'll try something new and cause something else to break. I have a laptop that has been running for 18+ months without any issues. But that is web browsing and light text editing.
So the distro is stable just depends on how much you tinker with it, but that's true for all distros
I will second the Roku. I tried this a few years ago and kept running into issues. Some sites like Netflix don't offer HD resolution on PC. Then there are other services that have sketchy support for Linux. HBO and peacock are 2 examples.
I use my PC for personal streaming and a Roku for the main TV