The solution is to give them a taste of better built (specifically competetive) games and they will never like roblox.

In my experience, this doesn't work. The primary reason being that most of their friends are playing Roblox and if they are consuming any content on the internet, much of it at their age is related to Roblox.

Our kids have never been allowed to play, and it still comes up somewhat regularly despite all the various games and consoles they have available.