Hi @SPwulf ,
These rollup web parts are classic web parts, it is only available for classice page. For modern sites, you can only use modern web parts. These are OOB modern web parts you could use in modern page: using-web-parts-on-sharepoint-pages
You could create a classic page to use the Conent Query Web Part by following this: go to Site Contents-> Site Pages Library-> New-> choose wiki page.
If you have to use modern page, Highlighted Content web part is the best option for you to dynamically display content from your site. use-the-highlighted-content-web-part
There is no query builder in the Highlighted Content web part, but you could choose filter and using multiple filters in the UI. This much eaiser than query builder.