@flamingofridays I’m assuming you’re the OP - one problem can be that once we are in an uncomfortable situation like that we can sort of put it on a pedestal and it becomes more and more grating and wearing and difficult to put up with - and it sounds like you’ve got to that point.
You need to let it go. I know that sounds simple but you just need to stop bothering about them coming round - just greet them breezily, ask them how their week was and leave them to it. Have your own relaxing plans and indulge yourself in your own space, preferably with some noise excluding headphones. It’s the only way you are going to get through it with a semblance of happiness and without causing ructions in your household.
They might be annoying you on purpose but from their point of view it is probably quite hurtful to be disliked by an adult and if they sense this then perhaps this will encourage them even further to disregard you and your feelings in your own home. It’s not to say you’re to blame, it’s just how they could be feeling.
Lastly, people really aren’t wrong when they say you have a DH problem - I’m not sure what he can really do towards adult children at this point apart from to point out that the way they bicker is childish, please stop in my home, or at the very least he could tell them that if they are pissing each other off so easily weekend after weekend, they need to go out and do something.
What he could do though is be more emotionally supportive of you. However you also again need to consider his feelings toward the whole situation and have some empathy for why this may be difficult for him as well.
If all that has already been done and discussing their behaviour with him just leads to pointless arguments with no changes then go back to plan A - ignore and look after yourself when they are there, and work on building a closer relationship with DH when they are not to diffuse tensions.