Do it manually. So look for sites that are in the top 100 for your desired keyword, do outreach to them and try to get them to link to you. Also, see where they get their backlinks from, and do outreach to those sites as well.
There, manual outreach. Google for templates, and how to select the websites for relevancy and authority and try to negotiate the pricing down. Hire a freelancer if you can't do it yourself.
People who claim manual outreach but then give lists of sites are a bit sketchy in my opinion. True outreach would be based on your needs, not on the sites that they have which "could fit" your needs.