Filtering and sorting reviews
The short answer
Filters decide which reviews appear in the widget. Sorting decides in what order. Both live on the Settings tab and both apply within the 100 most recent reviews collected per source.
Filtering never changes the rating you display — that always comes from the source.
The filters available
Show reviews only with text hides ratings left without a written review. Show reviews only with photos does the equivalent for images. Rating at least sets a floor. Total number to show caps the count. Exclude and include work on a reviewer name or a keyword in the review body.
Keyword filters apply to automatically collected reviews. Manually added reviews are already yours to choose, so you control those by adding or hiding them individually.
Sorting
Four options: most recent first, highest rated first, reviews with photos first, or random. Most recent is the sensible default — a visitor is asking whether you are good now.
What filtering does not do
It does not change your average rating or review count in the header. Those always come from the source. It does not touch anything on the platform itself, and it does not delete anything — a filtered review is hidden from your site and nowhere else.