When I am looking for backlinks I look at these things:
1. Ahrefs UR of refering page + manual review of backlinks to referring page - it should be not a spam and should have backlinks itself (i am talking about dofollows).
2. OBL of referring page - if it has many of it - it will pass very low link juice to your site.
3. I am not looking at traffic of referring page -
https://ahrefs.com/blog/links-with-traffic-study/
Most of link seller are mentioning high traffic to their sites and due to this they rise prices of links to rocket high.
As about traffic - I have couple of sidebar links from homepages of sites with 7-10M monthly traffic. And i have ~60 clicks monthly from that links
People goes to porn sites for masturbation, not for reading content and clicking some links.