Take a look at the post Let users filter data in a table for a discussion regarding more complex filters.
You can use multiple dropdowns in a filter like this:
export function filterButton_onClick() {
$w("#dataset1").setFilter(wixData.filter()
.contains("type", $w("#selection1").value)
.contains("title", $w("#selection2").value)
);
})
In the above example, #selection1 and #selection2 are the two dropdown menus. Together they will filter the query.
Look at the wix-data.filter API for more information.
Good luck,
Yisrael