Serious question, but how does Preston always now when a settlement is in trouble? Do they radio in? Do they send someone out to find help? Does he have black shaman magic? What's the official answer?
Well the very first people you help mention sending word with the traveling merchants, so presumably before you retake the Castle he just gets word from passing travelers.
probably through radio. you know the bug antena at the castle? they have a guy dedicated to just sit there and listen. so i asume hes listening for emergency calls.
Is there any way to turn those quests off? like seriously I have a level 70 character and all the settlements set up and they are constantly under attack or need help.
nah
defense stuff breaks down, you don't get your handful of caps every day, and that's about it
Settlers don't die or disappear, crops still create food, you get all the good stuff minus a few caps which you don't really need cuz it's a Bethesda games
there's no challenge to any of it