Videos take a long time to buffer
This is a known issue, and is due to YouTube throttling the download speed of videos. We are working to find a workaround for this, collaboarively with other projects. You could try using a different instance to work around the issue.
“It’s not working most of the time”
Try another instance, instances in the instance switcher are checked to be working every minute. You likely want to choose an instance with a high uptime too.