I do not know of any open-world game that does not attract this kind of stuff, especially when players are of all age groups and global. This is not new. I know it is sometimes not practical or possible for many players, but if it is possible, you can look around at other official servers that have better reputations, or just go to a private, moderated server - or even rent your own, password it, and invite a core group of friends to play on it.
I have found though, that the small minded that do the spam-build and blocking behaviour often don’t have the staying power. They are often adrenaline junkies that thrive on bullying/abusive actions, but then often move on to another server to rinse and repeat. You can defeat this action by trying to hide your stuff and keeping track of when they are online.
You can screenshot and report, but since there are far too many official servers and simply no credible way to police incidents globally. Also, ANY PvP game has players trying to find exploits, have imagined axes to grind with other people and resort to online as it’s ‘safe’. Check though either of the following channels. They are checked and acted on where possible/necessary:
https://www.conanexiles.com/exploithunters/
https://forums.funcom.com/t/conan-exiles-forum-community-guidelines/54375
I would check out the private servers in your global zone and see what you think, otherwise use the above links to report.