It depends on what it is about Disqus you are looking to emulate.
https://www.ads-software.com/plugins/search/comment+system/
https://www.google.com/search?q=wordpress+comment+system
Try a few and see what you think. If they are not outright free, many should at least be free to try.
You may find one that is pretty good but is lacking one particular element. If it’s a well written plugin, it should be extendable with custom code to get what you need.
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