Best way to create a question that will be the basis for others (with dashboard filter)

I created question that is native SQL, inside this question I defined variable, so that I can then use a (text) filter in dashboard. This works fine.

Then I created a new question/chart from this saved question and wanted to set the same (text) filter in the dashboard for this chart. But the dashboard does not offer me to select this variable/column for filtering. Why ?
Is it because I created a variable in the original SQL question ? What is the correct approach?

Hi @CZvacko
Currently pass-thru of variables is not supported, but there are some workarounds in the comments: - upvote by clicking :+1: on the first post

Thanks, but I'm not sure how to use the mentioned workaround. The original question is native SQL, but the new one is Custom question.

@CZvacko That is not possible currently.