Self bets encourage more bets in the bet server, which is what bet servers are for.
You pay for your nudges and you are given a nudge, the Self-better also is paying but at a much higher rate, thus getting a better position.
It's not unfair at all, to get that position they put a lot more at risk, and whilst doing so they also create more bets for the server with added HYPE.
I do not support removing the self bet system, but I have a possible solution to your problem.
Maybe have a limit on the amount of self bets you can do in succession,
for example; one player buys 3 self bet nudges in a row and then cannot buy another until a certain amount of games have been played.