I know what you mean, as this happens to me ALL the time. It's become so annoying that I am very seriously considering making a new Apple ID for the main stuff that's a random set of letters and numbers, then use the old one for email only. My old one is from the iTools days, very short and simple and a LOT of people accidentally put it in instead of theirs, plus they try to hack it all the time.
I would first make sure you have 2-Factor on. Then put in the most complicated password it will take using a 3rd party password generating app, and change that once every few months. This won't stop them from trying but will make sure they can't get in.
Note also that once you are locked out, it logs you out of Messages and FaceTime on any other device, so you have re-login to all of those as well over and over each time it happens, and you'll lose any Messages that were sent to your, say iPad or Macs or iPod Touches etc, ALL OF THEM (repeatedly), during that time when it was locked. They'll still be on your phone however.
I personally think Apple needs to beef up the system so a lockout isn't possible. If someone tries to get into an account more then a few times and they don't get the 2-Factor right, just block them and make them call in to prove they are the real user. That way you can just copy your long complex password and paste it in and never get locked out and they do with no ill effects to you.
I have weeks were it happens so often I don't even bother logging into anything but my iPad since I use it often. So my Mac's Messaging is missing huge chunks.
Very annoying. Sorry you have to deal with it. Maybe Apple will do something one day to make sure us real owners of the accounts aren't punished by forcing a more powerful 2-Factor or even a 3-Factor where it makes you prove you are you or lets you know someone is trying and you hit "lock" and they are locked out by IP from ever trying to use it again. Who knows.
It's frustrating for sure. I just literally had to do the unlock on my phone, then re-enter the login/pass for everything on my devices a few minutes ago actually. Lost a bunch of messages and a bit of my patience with it.
Sorry man.
