A latest comments block allows you to display a list of your most recent blog post comments. This is essentiall the Recent Comments Widget available to you in a block that can be added anywhere in the content of your post.
Step 1- Hover your mouse over the Add Block icon (the plus sign in the upper left hand corner within the Gutenberg editor). Scroll to Widgets. Select Latest Comments.
Step 2 - The latest comments block will appear. You’ll see your most recent comments appear within the block.
Step 3- The sub menu above the block will allow you to change the text alignment. The block menu on the right allows you to further customize how the comments will be displayed on your page. such as showing the avatar or date as well as the number of comments that you'd like to be shown.