Good news! Now you can combine source and widget level filters, so they would work together (no need to create source variants or different filters anymore).

Step 1. Add a source-level filter for the source you are using:

Step 2. Click on a widget where you want to combine source and widget-level filters and click on the + Add a filter button:

Step 3. You will see the updated widget filter modal in the filter pop-up window. At the top of it, you can see the source filter. Below it is an operator (in the screenshot below, filters are joined with the AND operator). Lastly, you can add the widget level filter, combining your source and widget filters: