I’m generally skeptical about the effectiveness of “dark web monitoring”, as the vast majority of the internet isn’t indexed.
Having someone continuously monitor until something is indexed can be pretty useful for damage control, but in no way would this be a guarantee your information isn’t up for sale somewhere in the dark web.
Personally, I’m quite sure I won’t show up anywhere, but I know there was an 800 million record breach of the Aadhaar system, and I’d say there’s about a 75% chance I will be on that breach.
There are probably hundreds of exposed databases that have been that way for years with our credentials or posts waiting for a crawler to index it.