22 listings can still get you lots of sales. But those listings need to be that much better in quality to make up for the lack of quantity. Keep in mind that you are competing with shops that have over 1,000 listings selling similar items.
A quality listing means the item for sale is highly desirable, the photos are great, the price is right, and the title, tags, and descriptions not only tell people what they are buying, but are search engine optimized. If your listings lack in any of these areas, either fix those deficits or add more so you can be found by more (but ideally a combo of both).
Actually (just looked at your shop), improve your SEO first, then add more listings.