They are probably bot accounts and they will ditch the account and create a new one and spam the same thing again. I think the only way to combat this would be to make registration harder. The points of evil system only prevents a small minority of scammers and other bad members from signing up.
I agree with the registration to become more difficult and technical so that bots or fraud users will not enter this forum easily. Scammers will have a hard time to invade this forum if it prioritizes the security of its system. If they don't start to make a simple step to prevent scamming, it will surely get worsen.
I think our best option would be to making registration harder by including randomly generated questions related to the forum so they are both being taught how to use the forum as well as having to answer questions about it.
Questions related to a forum will really help the system to identify if they are really willing to learn or they will just do some scams in this forum.
Another option would be the shadow ban that has been talked about a lot. I think this would probably be the most effective way although again for this specific scammer attack they would learn to get approved by a staff member and then continue on their way of scamming but this would probably stop bots being able to easily exploit the forum.
This shadow banning can minimize the number of their victims and bots who are used in scamming and circulating in a system will be prevented to see publicly.
This will become their restriction when they enter a forum, they will not be easily seen by other people.
Why not automatically temp ban people whose topic titles are similar enough to the ones OP mentioned, and have it expire for a week or so? Most scam topics have something like "[WORKING]" or "✔️Verified" or "Earn up to {x} BTC" so an automated banning bot can look for those key words.
They are using those capitalization and positive words that's why some of their topic titles are beautiful to read. But in reality, it is very obvious and too suspicious whenever I see a title like that. We should always check the content and its legitimacy before engaging to those kind of information.