I think I found a better way, building on your idea. What I use is the following xpath:
(//div[@aria-label="Collection of Marketplace items"]//span[@aria-hidden="true"])[position()<=8]
This checks the title and location of the first 4 results on the Marketplace search page. Remove [position()<=8] for checking every result loaded without scrolling. Change 8 to 2 to only check the first result.
Be aware that the URL doesn’t contain the search location and radius info, so if you change those when you manually search, your Distill monitors might trigger, since they’ll also use the modified location. If the location and radius is stored client-side, than a separate container in Firefox or using the desktop app might solve this issue, but I’m not sure, since manually resetting them to a single value for all my searches is sufficient for me.