The Tldr; here is that your budget is too low to do anything meaningful on FB.
In the simplest terms, FB traffic is mostly garbage unless you're optimizing for purchases, and those clicks are easily gonna be in the $.5-$1 range these days. It's gotten expensive. If you're getting that many clicks for ~$15, I can tell you're running a Traffic objective and that's just gonna be garbage regardless. l
That said, you're on the right track with the retargeting, but even then, you're not running enough in the first place for retargeting to work. It takes a relatively larger data set.
I wouldn't bother running FB traffic if I can't spend at least $50/day, maybe $100/day.
I realize that most people cannot just throw that kind of money into the pit though.
So, to make this work you need a well planned and executed funnel, product, etc. which is beyond the scope of this discussion, but that's kind of the reality:
Running ads on any platform for $15/day in 2022, is basically worthless. It's sort of a lame reality, but it is what it is really. If you're interested in diving deep into this, I would be happy to help and could point you towards some good resources for learning though.
Also, one last thing:
FB analytics is basically un-trustable garbage and it's know that the data is going to be worthless. All serious media-buyers (people who run ads) use third party tracking software.