I actually get your frustration OP , I have a low threshold for noise , which started a few years ago due to an issue with near neighbours. So I understand the anxiety feeling when you can’t relax as noise invades every room of your house from an outside source.
Then I see so many comments on this thread saying you should just accept that being disturbed daily in your own home by the noise of neighbours is fine . What I don’t understand is why people feel the need to be so loud that it can be heard inside others homes , eg loud music in gardens , shouting rather than talking .
I think people underestimate the effect their “enjoying their garden “ can have on others when it comes to noise , or they simply are anti social and don’t care .
it’s important to balance your own anger at this issue . Eg it’s actually fine for kids to play outside , and sometimes they will have the odd scream etc , it’s fine for everyone to enjoy their garden and you may hear some noise , as once the noise anxiety sets in , the smallest noise puts you on edge as well as the problem ones .
I would be tempted to go round when you are feeling calm , not specifically to complain about the party , but to have a general chat about how noise carries in your area , and whatever bothers you most eg loud music , and ask if they could have a lower setting for that . Have realistic requirements, and ask for a small adjustment from them over what causes you the most stress .