Went through something similar, I had a stash of 10 embryos after having one child from the batch.
With 14 embryos left though, that is a lot of potential.
Are these embryos blasts?
How were they graded? Did they already use the "best" graded embryos for the fresh and FETs?
What are the clinic stats for FET?
In my case I was able to figure out that it was indeed an embryo issue that caused my FETs to fail, it wasn't me and I did not need further immune treatments. I had to do another fresh cycle with the same donor.