I am surprised you can claim listings, but not vendors.
Specially on a theme like ExpertHive, you’re looking for Experts, not their listings.
The vendor is the core, the listings are just offspring…
You could have access to professional directory, show the basic data from the expert, and let them complete it. It’s quite an incentive for people to appear where their peers already are, just by clicking a link, than going through the whole registration process.
So if that’s not too much of a redo compared to “Claim listings”, it would be a nice-to-have feature.