The real reason why Sam of FTX decided to part ways with Binance partnership is because Binance don't to follow the law and just contented on dodging the law by changing there headquarters location regularly. I don't know about Kucoin but FTX is the one showing cooperation to the law and happily complying with it. I trust Sam and most of the project that they are working with like Serum and Solana.
It is part of reasons only.
Sam SBF and FTX decided to separate from Binance because they now would prefer to compete against Binance. They think their exchange are growing up and big enough to compete against top exchanges exclusively Binance.
I don't think the separation is simply because issues of Binance with law, regulations, etc. FTX on their side are very careful to meet regulations and do preventive activities against law suits. It is a good strategy to build up a trusted exchange without or with at least drama as possible.
My vote goes to FTX is also because they give very cheap withdrawal fee for users.
Isn't the Alemeda group notorious for pumping and dumping, basically using their users and leaving them high and dry?