I genuinely think it depends on the family and the people involved. Also I'm afraid at some ages DC don't always have the wherewithal to understand complexities.
My DC would tell you they want exdh , me , dp and nana living altogether. The most likely issue there would be nana and I killing each other at some point.
Exdh wasn't abusive but when we fell out of love the atmosphere became really toxic. We ar both nice people (I mean in the main...I'm less nice when someone drives 30 miles an hour on a 60 road in the outside lane). We co parent really well , there is no animosity. However the only two people who really know what it was like at the end of our marriage were exdh and I. It wasn't screaming and shouting but it was cold , very cold. We avoided each other , frankly the DC probably see us more in the same room amicably now than they did then.
You honestly can't comment on it until you've been inside it. No , of course my children would have preferred us to stay together , they are 7 and 4 , what child has the emotional maturity to say otherwise?
However they would have grown up believing marriage was about parents coexisting , polite strained discussions and separate lives.
It took a long time for my DP to be involved in the family in anyway. However now , whilst things are far from perfect (anyone who claims their family is perfect is lying) they see genuine love at home. A couple that has common ground, laughter and affection. They see stability and partnership. They also see that their father and I work together for their good. They know we talk and share stories and photos.
We have all worked very hard to give them the best option of it all. I didn't want my marriage to die nor did I want to uproot them. However I am absolutely sure they are seeing a healthier happier family dynamic. Do not underestimate how incredibly hard some parents work to make the home a healthy environment.
Toxic doesn't have to mean abusive and screaming and shouting but when you've lived in a toxic relationship that has developed form two normal "nice " people you understand how pervasive and unpleasant it can be for all of those involved. Trying not to be nasty but it's not really ok to make snap silly judgements until you have experienced it yourself.