I think tax is a reasonable feature on a server for many different reasons. Tax is a way to limit profits, as the methods that are taxed (coinflip, auction house, sell chests) are very fast ways of making money, without tax it will just boost certain players ahead and make it harder for the less experienced players.
Specifically relating to coinfip, the tax also deters stat boosting, if there was no tax you could easily keep doing large coinflips to boost your stats, and then just have people pay you back. With the tax this reduces chances of boosting.
Tax is also a real life thing, and maybe it’s teaching younger players that everything comes at a cost, so maybe it could actually be beneficial for people’s personal growth?
If you don’t like taxes, you’ll have to get used to it. Irl taxes are a lot higher than 7% lmao