I can recommend buying, reading and implementing these
The New Strong-Willed Child https://www.amazon.com/dp/141439134X/ref=cm_sw_r_cp_api_aetSBbWSF5FX1
Raising Your Spirited Child, Third Edition: A Guide for Parents Whose Child Is More Intense, Sensitive, Perceptive, Persistent, and Energetic https://www.amazon.com/dp/0062403060/ref=cm_sw_r_cp_api_AftSBbMH5EADB
Kids behavior is a control mechanism to get what they want, and although every child is different, you can break down behaviors into one of four or five categories. These books help you understand their behavior better and give you effective, proven strategies to deal with it. All you have to do is not give up, not give in, and be consistent.
You’ve got to learn how to effectively discipline this little monster before it ruins all the kids childhoods.
Here's another one: "strong willed". My god, it might be even worse.
>So now, here we are, struggling to figure out what to do with the kids bc they get out of school at 2:25 and we all work. I work from home so I’m stopping my work day to go pick them up with my 5 month old instead of just sending them to daycare like normal kids.
I strongly suggest turning this problem into an opportunity. Kids can't go to daycare because SD6 got kicked out again? Well now, little Miss SD6 can go straight to her bedroom when she gets home with no snacks and no electronics and stay there alone until dinner time. Day after day after day until you find another childcare situation.
Sounds a little unreasonable, but if at all possible I would also call up the last daycare and ask if the other kids can continue to attend. Just not SD6. Cause it's going to drive that point home even harder if the other kids get to play with their friends after school while she has to sit alone with no electronics in her room. It will be money for the other kid's daycare well spent. Just do that until you find a new daycare that will take all of the kids.
I would also make sure that the new daycare knows that, no matter what day it is, if SD6 gets in trouble and needs to come home they are always to call dad first. Then either you or dad pick her up and it's straight back to sit alone in her room with no electronics until BM picks her up.
If it's any consolation, I don't think there is anything seriously wrong with her. If there was she wouldn't be able to control her behavior so that she only acts out during BM's parenting time. She is just a bold strong willed child who needs a firm hand. When not being in school or daycare is a worse alternative than staying there she will modify her behavior.
I highly recommend this book: https://www.amazon.com/New-Strong-Willed-Child-James-Dobson/dp/141439134X/ref=sr_1_1?crid=3I02EMMNXZNBZ&dchild=1&keywords=the+strong+willed+child+by+dr.+james+dobson&qid=1603806054&s=books&sprefix=the+stron%2Caps%2C174&sr=1-1
I raised a strong willed daughter myself and some days it was definitely a challenge. I once had to actually switch her daycare, to find one that was less warm and fuzzy, because she had every teacher there completely catering to her every whim. She was 3. So yes, I have been there.