I'm interested in other alternatives, hopefully easy to integrate like Disqus was. Also interested if comments can be migrated too.
Some people use twitter as the commenting system. You assign each post a unique hashtag. People comment on the post by incorporating the hashtag in their tweets. On the post page, i think there is a way to show tweets using that unique hashtag
I do it this way because my target audience is almost all on LinkedIn, and it allows me to keep any discussion (however little there is) in one place.
HOWTO: https://meta.discourse.org/t/embed-discourse-comments-on-ano...
Many years ago I tried using Facebook: https://developers.facebook.com/docs/plugins/comments/
Not too difficult to do with Vercel, Cloudflare etc.
Personally I'm comments off. Some people tweet compliments. Nobody tweets anything mean.
So I thought about adding a link on each blog post to a unique reddit post on my own subreddit. Most people have reddit.
One downside is that you have to have two windows open if you want to comment while copying snippets from the post.
Another option was Web annotation, but the standard and the infrastructure needed to make it work look massively complicated.
I'm currently building a static blog for myself. For my own blog, I will probably link it to my mastodon for commenting.