I have no idea anymore..

Not sure what I’m here to ask, maybe just to vent.. I have 5 kids. My older 3 with one ex, my younger 2 with another. My life is a mess and I’ve ended up in really shitty relationships. When I separated from my first ex, I had been seeing a psychologist, who helped me over the course of 2.5 years to leave. I struggled emotionally and with a lot of guilt. My kids were 4, 3 and 1 at the time. I had been advised by a DV counsellor, my solicitor and psychologist not to allow my ex to have time with the kids initially (they were scared of him and didn’t want to go). I got calls from him, his mum. Our family GP at the time told me he was a sick man and I was being hard on him. I eventually caved and allowed supervised time that gradually became unsupervised and increased to the current alternate weekends they spend with him and half of school holidays. They’re now 10, 9 and almost 8. They love going to their dad’s. He buys them everything they want (he runs a multi-million dollar business). They do all the fun things with him - holidays away/stays in the city, his house is huge and has 3 different play rooms set up for them, he’s installing a lift, there’s a flying fox, they’re getting a pool.. the list goes on. They remind me all the time how much better it is with dad. We rent a comfortable house but living in Sydney is expensive, we don’t have many of the luxuries they get at their dad’s when they’re here with me. (Before any assumptions are made, as people who know me do, he is dodgy and has an amazing accountant.. I didn’t go for a big settlement and despite the fact that when we first separated, the child support assessment based on his previous year tax return put his payments in the highest bracket, I had never known his income until I received that first assessment. He then did his tax return that year showing a dramatic decrease in his income and also further offset 80k into my name through a trust company that had been set up for our kids. Since then, he has been 2 tax returns behind and pays far less child support than he “should”. I could take steps to correct this however, it would not only infuriate him, it could also ruin his business and his business partners, the 50+ staff they employ and in the long run, my kids would all be affected). He constantly reminds me how much I’ve f*d up in life because I’ve had to move 4 times since we separated and I had another failed relationship involving children. He tells my kids “mum should (be doing this with her life)”, “mum shouldn’t have had any more kids. They’re not your real siblings”, “you should tell mum that you don’t want her to (do this)”.. my daughter (10) has become super controlling over me. She tells me what I should and shouldn’t be doing. She accuses me of lying (I don’t lie to my kids. I am honest in age appropriate ways and I tell them when certain things are not appropriate conversations to be had at the ages my kids are). I have no idea what more to say. She and I clash and argue all the time. She tells me she doesn’t want me to have anyone in my life and that I need to be alone now because I had “too many men”. She believes every word her dad tells her, even when they are obvious and blatant lies. Eg. He told them he never drinks alcohol. Then they saw a photo of him holding a beer and my daughter sat there justifying why he was holding it, that it mustn’t be his, it can’t be his. I explained it’s ok for adults to occasionally have an alcoholic drink, as long as it’s done responsibly, etc. she still could not accept that he may have had a beer. That’s one example of so many but my daughter in particular is convinced he can do no wrong and everything he says is the absolute reality. I have tried to get her into counselling but have court orders and require dad’s signature also. He has refused. She sees her school counsellor and refuses to talk about her dad at all. The school counsellor has told me she is living in a fantasy and isn’t seeing reality in certain situations. Essentially, she is believing what her dad has said over what the actual reality is, even when she is living and seeing the reality on a daily basis. My kids recently spent their 3 weeks of these school holidays with their dad and I received a message from him on the day they were returned to me, stating that when the kids went into his care 3 weeks ago, they were undernourished and since he had them, he has fed them “ a balanced diet of meats, carbs, fruit & veg, healthy fats, vitamins, etc and sleep well”. He says he has returned them to me in good health, claims he measured and weighed them upon arrival and on their last day with him and that they all grew taller and put on weight in those 3 weeks, and their cheeks are now glowing. He claims in the message that my kids tell him I do not feed them properly and says I do not wash them properly. He showers them still at his house to make sure they are clean. Apparently this is normal/expected? He says my kids shouldn’t ”have to” make themselves toast/cereal for breakfast. He mentions my daughter’s behaviour has become manipulative and that the 3 of them “lie to get their way”, a behaviour he says they got from me. It is a very lengthy message. I just don’t know what to do anymore. It’s never been easy coparenting with this person. He told my last partner and I on first meeting to make sure we didn’t get married or have kids. He accused last partner of sexually assaulting my daughter (did NOT happen) in front of her face and kept telling my kids not to talk to my partner, despite living with him for 3 years, because it made him angry to think that they were living with another man who wasn’t their real dad. I thought when he himself found a new partner (2 years ago) things would settle down, but both he and his new partner have verbally attacked me when dropping my kids back off to me. My kids were horrified because it escalated and they would not open the car to let the kids out and then he asked them if they wanted to stay with him or come back home to me. They just stared at him blankly and I reassured them there was no wrong answer and started crying. He laughed sarcastically and said I needed to get over myself and stop manipulating my kids and his partner said I was absolutely pathetic. One of my kids suggested they go back to dad’s one more night and come home to me the next morning and that was what happened. He doesn’t communicate changes from the court order plans with me, he messages my daughter on her device and expects the message to be relayed (sometimes it is, sometimes it isn’t). He bought her a phone recently that he controls through his. I can barely get through to them when they stay with him but he contacts her any time he wants (I limited her time in it when he wouldn’t allow me to share/contribute to the control/restriction codes. It has the phone numbers of his family and his partner’s family members in the phone but I can’t even add my family in because the controls block these types of actions without the passcode). He told me I’m being unfair on my daughter and I’m controlling.. My daughter thinks the same. I just don’t know anymore. I feel like I’m constantly fighting a losing battle. There’s so much more I could type in here but it’s pointless. It gets me nowhere. I can’t help my kids. Especially my daughter. I’m so scared she’s going to be completely psychologically destroyed and I have no idea where to start to fix any of it. I don’t want my kids to think I’m a bad mum or that I failed them. I don’t want to fail them at all..
Thank you for reading.