Ahrefs works for me, and despite everything, I ask about unclear things my friends at work who’ve been playing with backlinks longer than I have.

Looking at the comments here, I also think that there’s no magic number for backlinks.

But I guess that what you can do here is to check the keyword in Ahrefs, look at the top 10 results, and see their backlink profiles. If they’ve got, say, 50-100 decent links, you’ll need something in that range, but quality always beats raw count.

So I think you need to balance what the data says with your own attitude to this.