Issues in anatomy scans (csp missing)

I had NIPT test and MSAFP test done before which showed negative for everything which was great. But when I went in for my anatomy scan when I was 19w+3days it showed couple of issues:

i) Possibility of CSP missing in the brain (the dr could not verify this due to baby's position but the tech who performed the US said was quite confident on this)

ii) Baby measuring small around 10-12 days behind (I am south asian if that helps)

After the US based on the MFM recommendation we had fetal echo for the heart and met with the genetic counselor today.

iii) echo looked reassuring except for pulmonary artery is a little enlarged where they want to monitor again in 4 weeks. Everything else looked good.

iv) the genetic counselor gave an option to do amniocentesis.

We don't know for now if i, ii and iii above are connected. We have a follow up fetal MRI and ultrasound next week where I will be 21weeks+5 days and I will likely know the result only in 22 weeks from the MRI.

We are trying to decide if we should wait for the MRI result before doing the aminocentosis given the risk of miscarriage with amino. If the fetal MRI shows everything is normal we might not want to do amino. But if the MRI shows some abnormality (esp isolated CSP missing or some grey area diagnosis) then we might want to do amino. They said it will take 7-16 days so I might not be able to get the amino results within 24 weeks if we decide to do it after the MRI. I can either do the amino this week and take the miscarriage risk and find out everything is normal in the MRI next week or wait until after the MRI.

We have decided that if the MRI shows CSP missing along with other brain abnormalities we might likely decide to TFMR but if its only isolated case of CSP missing but no other brain abnormalities then we are struggling to find enough data on the outcomes where the amino test results might be useful to make our decision. I have been told that CSP missing is a very rare case. So even though the amino risk is small after having a rare diagnosis I would rather not take the risk. Looking for someone with similar experience.