After Gravatar avatars were blocked, I switched back to the built-in comments system from Duoshuo. Overall, the built-in comments load faster, but they have weaker functionality compared to Duoshuo. In any case, there are pros and cons to both options. Now, let's address the issue that arises after switching back to the built-in comments.

When I try to leave a comment as a visitor, it takes several tens of seconds to succeed. Later, I discovered that this was caused by improper settings in the backend. The solution is as follows:

In the backend, go to "Settings -> Discussion -> When a comment is posted" and uncheck the boxes next to "Email me whenever" someone posts a comment and "A comment is held for moderation". By doing this, when a user leaves a comment, it will no longer send an email notification, which significantly improves the speed. This setting does not affect the "comment reply notification" function.