Oh yeah, Declan Murphy! I remember now and I second your plea to hopefully never have to see him again. That character was just....ugh. And when you consider Amanda's history with her old boss from Atlanta assaulting her, the fact that she slept with and get knocked up by her superior Murphy always made me uncomfortable.
MH's pregnancy was during the Neal Bear era where Olivia was not allowed to have a personal life so of course, they hid her pregnancy. The two subsequent showrunners really overcorrected and leaned too much into the personal side of things, but I never begrudged Olivia becoming a mother since we found out it was something she was interested in back in season 8 or 9 or whatever it was. Personally, I would have rather seen her foster or adopt an older child in the system because I think it would have made more sense for the character, but whatever.
When we first learned Kelli's second pregnancy was being written into the show and not hidden I thought maybe Amanda was going to come to realize she wants more children and intentionally get pregnant but instead it was more of an Opps! I did it again! scenario and not to put all the responsibility on her, because it takes two people to make a baby, but I do seriously have to wonder what her birth control method is.