Here are a couple tips to improve the usability of peertube.
Use sepiasearch when finding new peertube instances and videos. Some browsers such as firefox allows you to create a shortcut for searching
Subscribe to channels through your most used fediverse account. Then it will pop up in your feed and it’s easier to comment on videos.
Hm, have you tried from another peertube instance?
If that doesn’t work, have you tried subscribing from mastodon instead? I wrote instructions in an earlier reply.