Hi Honey, big hugs for you as I am sure it must be tough. But it will be better, I am sure.
So now regarding night sleep. Kiddos have to be properly tired to sleep well at night. So not UT or OT as both can result in inconsolable NW. It all depends on kid of course, some will wake earlier for the day, some will only cryout at night, some will do cot parties when UT and some will just sleep through no matter what. I think the most important thing to remember from BW is to understand that every child is different and try to find a solution working for both mother and the baby.
So with your routine, as Tracy said, no independent settling skills will help, if the routine is not ok...

. She advice going to 3 naps around 4mo not only because of feeding but also because proper A during day prevent NW at night which are a result of OT or UT. She doesn't state in her book every detail of the transition but I guess there is not place for that there:). Would that make sense? Imagine yourself if someone tell you to sleep when you are not sleepy, 4x times a day if you already don't need it. You firstly get annoyed as "com'on - I don't want to sleep" and later you can be just to wired to sleep at all.
With naps, it will take couple of days to get to new routine. Try to be patient, maybe help her with shh/pat when she wakes from OT and the nap was shorter than 1h. I really hope it will get better for you soon!