Anonymous tips are less than worthless.
The first problem is that anyone who is anonymously tipped on is just going to deny it. And now its the word of a named person vs an anonymous tip. That isn’t going to fly.
The next problem is that people will quickly learn to weaponize the anonymous tip process to persecute the people they dislike - regardless of whether the target was even involved in the vandalism.
Policies like these are dumb. They don’t discourage the bad behavior (the opposite, actually, perpetrators know that the damage they do will impact far more people, which is the entire point of doing it in the first place, so this policy actually works as an incentive to do more vandalism).
Are you just talking about dynamic DNS services for one or a few home servers?
There’s always DynDNS, but that’s a paid service. I actually discovered that dynamic IP address service was provided free by Google when using Google Domains as the registrar, so I moved a few of my private domains over to Google several years ago to save myself $55 a year.
Unfortunately, Google Domains is shutting down and all registrar services and existing customer domains are getting moved to squarespace and I’ve not yet been able to determine if squarespace is going to be offering the free dynamic DNS service or not.