Low risk NIPT results with lowish fetal fraction - indicative of placenta or other problems?

I got my NIPT results back yesterday, everything came back low-risk, which I’m very thankful for. I am a little concerned though, about the fetal fraction - 5.8% at 11w3d. I’m 13 weeks today. I know that as long as the ff is 4% that the results are reliable, so I’m not concerned about the accuracy of the results, just concerned that it’s indicative of another issue, especially a placental one.

Just a bit of background, I had one 9 week loss before I had my full-term daughter in 2018, and I had 2 chemical pregnancies in October and November of this past year. I had some tests run, and learned that I’m slightly hypothyroid, which surprised my doctor, as I’m very slightly underweight - BMI usually hovers around 18ish - and I didn’t have any of the hallmark symptoms. I’ve been properly medicated since, and got pregnant again in January. My last thyroid panel was run 2 days before the NIPT blood draw, and my numbers were great. Baby is growing well and has a solid heartbeat, but at my 7 week dating ultrasound, 2 small subchorionic hematomas were found. I had another scan last week to check if they resorbed (I have had zero bleeding) while waiting for the NIPT results, and Baby was actually measuring 5 days further ahead than we thought they would be based on the first scan, but both schs were still there, albeit small.

Does anyone have any wisdom or similar experiences with this? I would have thought that with my lowish weight, the fetal fraction would be at least 10! Can hypothyroidism affect the ff, even if medicated? Maybe I’m overanalyzing everything, but I feel like it’s been one thing after another and I want to start feeling secure in this pregnancy... thank you for reading.