Less talk, more action. Ask questions- listen and observe. Set boundaries. Push back and let all hell break loose.
You will get so much advise. Lots of it will be polar. All I can recommend it to do the best you can with what you know. Test the water with "New behavior" and see if R improves or gets worse.
Set intentions:"I want to just listen to spouse and understand their POV without taking their words personally" is much better than "I want better communication with spouse".
Set boundaries:Someone is yelling at you, Calmly say "I would like to understand your POV, but I can't until you speak calmly"
Stop doing what does not work. Do more of what works.
"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