Unfortunately, it seems to me that such devices only partially block the access of children, and especially teenagers, to sites that are not intended for children. In any school classroom there is always a computer genius, the same age as your children, who from an early age is well versed in how to get around all these protections.
Even without this othe children help. There’s a lot of available source in the internet to fix almost everything related to the gadget such as forum and youtube since internet gives the freedom to explore almost anything in the web.
A simple child restriction will only work for a short time because human always have the curiosity to explore those forbidden and try it for themselves. I were the parents, I will slowly educate them about gambling so that they can decide for their own that gambling is risky instead of giving them a restriction that will push them to explore more out of curiosity.