The code doesn't only affect the wpDiscuz plugin; the addons that may have added filter buttons also require changes.
The JS code we've provided should work fine.
You can also customize the class.WpdiscuzWalker.php file if you're familiar with PHP. More info here: https://wpdiscuz.com/docs/wpdiscuz-7/customization/custom-template-and-style/
In case you want to say thank you! 
We'd really appreciate if you leave a good review on the plugin page.
This is the best way to say thank you to this project and the support team.
(...) The JS code we've provided should work fine (...)
Worked, but I would still like to hide the comments sorting buttons too.
Please, could you change that code so that the comments sorting buttons are also hidden when there is only 2 comment?
Thanks in advance!
We will add a new function to the wpDiscuz core code so that if there is only one comment, all filtering/sorting buttons will not be displayed. Please wait for the next update (no ETA yet).
In case you want to say thank you!
We'd really appreciate if you leave a good review on the plugin page.
This is the best way to say thank you to this project and the support team.
I saw that v7.6.22 has fixed the problem and now the filtering buttons are visible only if there is at least one comment.
Thank you very much.
