I appreciate the response!
Yes, I'd honestly be quite relieved to learn simply obtaining more backlinks would solve this problem, because I've been smacking my head against the wall trying to figure out what else it could possibly be.
Still open to any other input, but this is a good answer - thank you.
On a related note, what would you say a site's DA is worth going for in terms of backlinks? I've heard conflicting views, but a lot of people have said as long as it's a relevant site, 30+ DA is ideal. Any thoughts on that?
Thanks again! I'll give it a while longer, but if noone has any other input I'll mark your answer as best.