How to comment on a lot of small expressions in QQ space comments?

The words on the PC side can be added to the expression. When you turn to the page I pointed to with the red arrow, there will be many expressions. As shown below, if the expression is not enough, you can copy it from the existing expression.

On the mobile side, it depends on whether an expression pack is installed on your mobile phone. If it is installed, you can click it one by one, and of course you can copy it into the existing Yan characters.

You can go to those websites to search for expression typesetting first, and copy it if you find something you like.