You seem to be under the impression that Roku and Chromecast don't do the exact same things.
There is no good solution because connecting a Pi or something is not as good as modern TVs without an AV1 decoder and it also doesn't have a good remote interface as far as I know.
These smart tvs just suck. All these integrated systems. Much better off having a seperate device like Roku or Chromecast.
You seem to be under the impression that Roku and Chromecast don't do the exact same things.
There is no good solution because connecting a Pi or something is not as good as modern TVs without an AV1 decoder and it also doesn't have a good remote interface as far as I know.