Yes, I can see what you mean.
It seems a shame to miss out on sharing so much with the only other people who will indulge your neuroses and tell you your children are brilliant for managing the utterly mundane.
Honestly, most of us want your child's speech to improve at nursery, are happy for you to moan if you haven't slept for weeks, are dying to hear funny stories about your children so we know that ours are no more bonkers than anyone else's.
"ping-ponging back and forth between positive and negative unsure where to pitch your conversation"
pitch it at assuming that most of us are decent humans doing our best and mostly a little at sea with the whole thing.
Also, some people really, genuinely, are great at this whole parenting lark - not the ones with babies that sleep through, but the ones that you watch and think "wow". I think it's OK to see someone who's doing a great job and admire them, and copy some of their techniques, without it meaning that you are a shit parent.
I hope you can be OK with other people thinking you are deranged and stop over-thinking these interactions. Being proud of your children is not being smug, being frustrated with them is not a sign of weakness. Most of us are making it up as we go along. And the ones who aren't are super, super nice and always willing to help.