Have you ever heard of "runners" or "beards"? I think there's even a movie about it. Not sure what's it called.

They are the people who bet on someone elses behalf because that someone can't bet because bookies either limited them to small stakes or they completely banned them because they won too much.

If you think there's no such thing as banning someone because they win, you are wrong and don't know anything about sportsbetting.

OP is betting mostly on small markets (low liquidity) and bookies don't like when you are constantly beating them. That's why sharp bettors get limited very fast, or even completely banned from using the sportsbook.