Possible ITP

Please advise. Newborn who presented with slight petechiae on thigh. Platelets checks and reverified hand count 10,000. NAID ruled out, by mother test and cleaned platelets given without much of a rise in level. Highest platelets at 26,000 after transfusions only to drop back down to teens within a couple of hours. 8 transfusions q 6 hours with platelets amounts starting 30,000 and last one 60,000 without much rise. Baby delivered vaginally (10 minutes of pushing) with hematoma not crossing fontanelles that is slowly resolving. Slight jaundice baby under bili lights 2 days with resolution and removal from lights. Head ultrasound no evidence of intracranial bleed. Mom negative for infections and infants received antibiotics prophylactic. All blood tests including HCT and clotting factors normal except for platelets. Baby given IVGx 4 doses with no rise in platelets. Infant 5 days old now with platelets still in teens besides getting multiple transfusions. Given Lasix. Abdominal scan done to rule out hemangiomas. All organs normal. Baby 8lbs 10 ounces at birth, eating and breastfeeding well with excellent latch and feeding has maintained weight. Algae scores 9,9. Excellent color still, petechiae on thighs resolved. Excellent tone, all reflexes normal, all vital signs normal. Cry normal. No bleeding from gums or bruising on lips from sucking no new bruising noted. During pricks with blood draws slow to bleed and clotting fine without oozing. Umbilical IV AND EKG normal. Mom had normal platelets at delivery and no excess bleeding with delivery. Mom did have 3 Covid vaccines during pregnancy and during month conceived had mild case of Covid with little symptoms. Maternal 2nd cousins infant was diagnosed with ITP AT 8 months with complete resolution few months later. Doctors stumped at this point. I’m a nurse and babies grandma any suggestions?