Consultation to sell space in web portal.

Hi I don't speak english so I hope the translation by Deepl is good.
I have a portal two years ago with dental clinics in all cities of the United States and Canada with over 200 thousand inhabitants, depending on the city the number of dental clinics listed on my site, are the services, map, address, contact phone and some text . I would like to contact these clinics that many already have top 5 or top 10 in Google and offer an outbound link and some personalized text for an annual payment of USD 100. Place this idea on UPWork and no one sent me a proposal, as I need someone to call in cold.
Do you think my idea is viable?
I appreciate suggestions to monetize since Adsense gives me very little and the traffic is 1000 a month all organic.
Thank you

Any comment can be valuable because I'm half lost, I published in UpWork and invited several for this work and no one responds either haha I put USD 100 as a background, maybe I do not focus well what I want, I do not know. Does anyone have experience selling space on your website?
Thanks