The base features аre free. Watch the full tutorial: https://www.youtube.com/watch?v=r4iX53Qg2sE
Yes, chronological order for posts is an extended feature available only for paid users. As you said it is the only way to see chronological community posts on a browser, so we can't provide it for free.
If you need it, become a supporter. It takes time to update the extension every time Youtube changes internally.