Sending you hugs as I'm in a similar boat. We are trying to figure out DD's schedule and how to make the right transition. The 4 month sleep regression is so tough.
I'm not positive, but maybe that last CN is too long/too close to BT maybe. I typically aim for a 12 hour day (I think I read that somewhere) though I'm having a hard time fitting a CN in, so that's where I'm struggling. I feel like your original schedule looked great, but you just needed that A time bumped and maybe the naps shortened a tad bit. What do you think?
There is this great app called the Wonder Weeks that you plug in your baby's due date and it gives you so much information from week to week along with the developments and what to expect. It helps me calm down when everything seems to be going to pot!