Is getting leads info and nurturing those leads is good for an early-stage startup to gain traction?

I run early-stage startups and what I found initially reaching out to the right prospect is very difficult. LinkedIn DM, Ads, are expensive. Writing content and social media branding is a slow route. Influencers are out of reach. We could find some people through incubators and accelerators but not the right sample. We found the tool that gives us active leads who are interested in our targeted areas. They use keywords, users activity, posts on main social media platforms to identify the right leads for us. Lead info includes emails, social media pages, websites, so on. If we nurture the right prospect on social media before emailing or reaching out through DM is it a good strategy and worth paying?