Using a web browser to watch livestreams on Twitch isn't always the best experience. Streams can crash or be laggy and choppy, and the ads are disruptive. If Twitch is unwatchable for you in browser, you might have a better experience watching it in a video player such as MPV or VLC.
Streamlink is a command line utility that allows you to open Twitch live streams in a video player of your choice, along with many other services. The Streamlink Twitch GUI is a helpful tool for browsing and opening Twitch streams, especially if you are not confident with using the command line. You will need to install Streamlink for StreamLink Twitch GUI to work.
Streamlink does not display Twitch chat. Here are some options for viewing Twitch chat alongside StreamLink.