Co- parenting is a super long road with a contentious ex. I know I'm not the only one who's done this a long time on here so I'm sure others can attest to the same thing.
I think for right now you can set strict boundaries, your decree should have everything spelled out as far as time with the kids. And I'm sure there are penalties. I know it's more money but if she keeps violating the court orders you can take her back to court. It's an option...(I wish there was a shrug emoji). I don't think this is a good time to just kind of let things slide. You may need to dig into the DBing bag and dig out some validation. But you may want to look into some co-parenting classes or books, or difficult communication books. I'd strongly suggest Difficult Conversations. I had to read it for a business related thing but there's a lot in there for more personal convos with difficult subject matter or difficult people. (Crucial Conversations will pop up when you search it. I've also read that for professional reasons. I think the Difficult book is much better applied to real life, and I prefer the methods.)
In the immediate I'd say things like:
-I'd really rather not deviate from the court order right now. I'd really like to stay on schedule for a little while until we get settled in to this routine. Maybe we can discuss day exchanges because of fun plans in the near future once were a little more practiced at this.
-No, I won't be giving up my time unless you plan on a fair day exchange 1 for 1. This is what's court order. I can bend on this so the kids won't be disappointed but that means you need to bend too.
-No, we can't do that. I'm sorry, you'll have to disappoint the kids but this is what's court ordered.
-I don't think it's necessary to assume the kids are struggling with every little change. No one likes change, but kids are resilient and if this change proves to be a continued problem we can address this down the line.
-I'm not saying that these kids aren't struggling, I'm not really seeing the same thing when they are with me. Could you be more explicit in why you feel that way so I can understand better?
-I don't really understand why the kids would worry for me while I'm hiking(etc). On our time I don't concern the kids with where you are or what you are doing on your time without them. That's your time just for you. They obviously miss you but they never worry. Can you help me to understand their anxiety around that better? I'd like to address that with them myself.
This kind of stuff works with my ex, and the exes of friends. I don't know how your ex will take it, but it's worth a try. Warning though, conversations like this are hit or miss with my H's ex. But she's not real good with deescalating conversations. She takes validation and any attempt at cooperation as patronizing even when it's sincere if she's in the wrong head space.
"What is best for my kids is best for me" Amor Fati Link to quotes: https://www.divorcebusting.com/forums/ubbthreads.php?ubb=showflat&Number=2879712