If you are playing on a server that has such a pay-to-win structure, you don't "join 'em." You report them and leave.
And there is nothing wrong with that. That is the kind of purpose that this tool is meant for.
The problem with this is the wording. The notion that something is an "unfair advantage" is very hard to prove if there is no clear and unambiguous "competition" that the players can use the materials in. I know that this "competition" is very clear on some forms of servers, but hardly on all servers that sell "high tier materials."
I mean, most of servers that i play you can pay 10$ dollars to get 64 stacks of diamond blocks without ever break a single dirt block while i have to spend plenty of time to get like15-30 diamonds or you pay 15$ dollars in the server's website to get 2 Iron Golem spawns and have an infinite iron farm, tell me if it is possible as normal player, what is more unfair, the player that pay to get infinite iron farm or a player with xray spending less time in caves to get some minerals, and not mention the swords with sharp X, unbreakable X and etc. idk i can only get unbreakable III after playing 8 hours (depending the server) and that is the hight tier a normal player can enchant.
I know, xray is illegal in most of the servers, but come on let me get a chance against the players who have never mined a ore with thousands of diamond blocks, with swords that can kill the ender dragon in one hit, armors that absorb the 99% of damage all because they spend real money in the server's website.