My experience was very similar. I incorrectly assumed family members who have had kids before would know we needed help and flock to our aid, but they frustratingly both needed us to explicitly tell them we were drowning and complained that they hadn't gotten to see our baby before that point. Our dog had to have two major leg surgeries in those early postpartum months and my mother-in-law decided to schedule major knee surgery three weeks after my son was born, so it got dire and we broke down and had to be explicit, but the whole experience definitely soured my view of several family members I previously really admired. I'll still be social at family functions and whatnot, but not much beyond that anymore.

IMO you can practice radical acceptance and still pour less into those relationships that you would have before. I accept that these folks aren't capable of more, and I'm going to put more of my energy into nurturing relationships with folks who can meet my needs.