Hi There!
Thanks for reaching out to us. I’d be happy to help here.
By default, the only tags that are available in the filter bar are the ones that have a post assigned to them.
Unfortunately, there is no built in way to achieve what you are looking for. If you were to accomplish that it would involve some custom coding.
As a workaround, taking the following code snippet as an example, you could customize the filter options to hide specific tags:
https://gist.github.com/vicskf/25dbbbf37566c217bee598b2d44344d5
I hope that helps. Let me know if you have other questions.
Best,
Victor