First two questions should stop bots, but it looks like real people spam.
Installing "stop forum spam" can help somewhat with this:
https://www.phpbb.com/customise/db/exte ... orum_spam/
Can't see images on phpBB site, but vB version allows to report spammers to their database. So spammers would have harder and harder times to register.
There also could be type of questions that asks something only EK players should know. But, that also could affect normal users. For example, if you ask who's first NPC you meet, someone maybe wouldn't know that Adaon is correct answer.
Controlling usergroup permissions also can have its set of problems. But, it can be achieved:
https://www.phpbb.com/community/viewtop ... &t=2371211
First usergroup can't post links (spammers basically love links), only content. After some time, or number of posts, user can be automatically promoted to normal usergroup.
Fighting spam is always hard and time consuming.
I also found this:
https://cleantalk.org/price https://www.phpbb.com/community/viewtopic.php?t=2183830 They ask for money, but not too much. Not sure how good they are and probably it doesn't stop real people, they say so.
This is official phpBB guide how to fight spam:
https://www.phpbb.com/community/viewtopic.php?t=1861645