We are thankfully quite a long way out the other side.
Communication was only ever via email. I did learn to deal with that. I found it became easier as time went on.
I stopped agreeing to everything because if I gave an inch he would take a mile. Before agreeing to anything I would ask why. Manly manly lies were shown up thus way.
I would use the grey rock technique, I literally never started a Communication unless there was an immediate need or it was information the court ordered me to give. I literally never rearranged contact myself, I either did stuff on my weekend or we didn't do it.
If I needed something i would wait until he wanted to cancel or change something, use that opportunity to make my request (while we are Communicating successfully DC need you to....) then only answer his request once he had answered mine.
I also used the broken record technique, first time I would state something with a reason and polite niceties, second time i would repeat the answer more simply with niceties, Third time onwards I would literally copy and paste the answer and nothing else. He learned that the answer he got at the start was as good as it was going to get.
If something Ex said was factually incorrect I would correct it with DD (eg I cant come your the play because there was no trains that day we would look it up on the app, or I came but you didn't see me when we had taken the time to stop and check the room just in case). If it was a matter opinion "Your dad has his perspective, I have mine, you might see it differently again". (Thr old recollections may vary long before it became popular). Teaching DD to hold onto her truth and reality whilst not aggravating her father became an ongoing tightrope.
Ex was slowly self restricting contact when he realised he couldn't use the kids to get at me. He literally was losing interest in them as it became apparent they didn't believe his bs either. Ds was a vast pain and disappoinent due to his sn. you do need to be aware actually got more dangerous for them the older they got and the more they challenged him when he lied or let them down. Eventually and very sadly he physically injured one and I was (just about no thanks to ss) able to stop contact.