Sounds like both my daughters and the entirety of the last 5 years of our lives. Let me tell you what I have learned.
Kids love to be engaged and something simple like sitting in a chair, being still, and taking bits of food one by one may very well be like any sane adult sitting in a 4 hour insurance seminar. If they're wiggling around, getting up and running, and generally being insane, then maybe food time isn't as enjoyable as they need it to be.
I'm not suggesting you do this because apparently people have problems with my particular style of entertainment - but I have found that my daughters love the detailed stories of the pancake people and the lake of syrup blood (or whatever food they're eating at the moment). As I tell the stories, I use their names, saying something like "the Sally monster then charged the village of the pancake lords, huffing and shining her teeth at their chief. One by one she took a tiny bite of each of them just to warn them what would happen if they tried to escape her wrath..." and yeah I'm pretty graphic with them but for the sake of illustration I'm not going to tone it down. Point is they love it when it's their turn to take a bite of the pancake huts, dip pancakes into the lake of syrup blood, or chomp down the mighty broccoli forest. As they grew they began telling me the stories too.
I came to this because asking them about school, and the routines of life would receive short, vague answers and could never sustain the length of a meal. But making up stories of food people always lasts for me. I don't have to do it every time. Some times I can just put a single candy corn in front of them and tell them every time they bite their food the candy corn's rope is pulled closer to them and they can eat it when it crosses some line. Sometimes they just eat on their own.
The general idea is that food time can be a chore if it is a constant battle. And through my many wars I have found a way to convert the battle into a story about the battle. And they eat now. Often on their own, but often they want stories. I am happy about that because I know some day they will no longer want my stories and they may be having their own in their minds while they eat.
It doesn't have to be airplanes and choo choo trains. It can be as simple as a goofy face every time they take a bite. But engagement was my answer and I am confident in their ability to feast upon the flesh of the raspberry village on their own without it turning into the destruction of the house in a movie like chase scene... been there before.
There are many sources relating to the benefits of family meals. One that links to many is this:
But that's making the assumption you're not doing this already. Hard to tell. It can be family meal time AND the total chaos at the same time. I know. Tune it to your liking. Stories of feasting savagery work for me. Maybe tales of princesses or ninja turtles would work for you.