This sounds very familiar. My husband's has done much of this.
Understand that you do not have to listen to her. She has drawn some hard lines with you, and she can only boss you around as much as you let her. Joint custody means you have as many rights as she does. If you don't approve of cell phones for a 10 year old (I personally don't), then tell your child to leave it at mom's or it is pulled when the child arrives at your house. It's that simple. Your child and ex will throw a fit, but if you stay calm and tell her your style of parenting is different, then there is little she can say. If she tries to argue about accessing the child at your house, then tell her you will agree to JOINT communication protocols if she wants to develop calling times for the child at BOTH houses. Otherwise, she gets just as much access as she has provided to you. What is good for the goose is good for the gander.
Also, unless your parenting plan explicitly allows her to plan activities on your time, JUST SAY NO. Or you can tell her, "Please provide the information and I will take our child to the appointment". By allowing her to take the child during your time, you are actually giving her evidence to go back to court. She can tell the courts that you "didn't want the child during that time". Trust me. My husband's ex tried that, and took him to court to get rid of joint custody. (Fortunately it didn't work, but we had to pay a lot of money fighting it.)
Depending on your region, sometimes a Guardian ad Litem can help. In our county, they don't have much power. But in some circumstances, they can work as the child's advocate to reduce bad parent behavior by bringing it to light.
Last, our kids are now becoming adults. And from experience, if we could do it over again, we would have worried less about that my husband's ex would do, and worry less about her exploding. We would have just parented as we saw fit in our house, and ignored her calls and demands for access. We would have hung up on her more often, demanded more emails, and given her less access to the kids when they were at our house.