If I have big amount of money that I can afford to risk, it's either I increase the stake or I reduce the stake, the choice is mine. But if I increase the stake I might not last longer before I run out of funds in my betting account and I might not enjoy the fun and you that might actually make me deposit another account if I can also afford to lose more, but if I reduce the stake I will probably gamble for longer period of time before I run out of money and my chances of winning increases. Even if there's no guarantee of winning in gamble, the more you gamble the more your chances to win will increase but if you don't gamble responsibly you might be addicted in the future.
No matter how much bankroll you put in, you still need a strategy you can use consistently. Sports betting isn’t just luck, if you have a solid strategy you really have a chance. The problem with most gamblers is even if they’re good at predicting, they lack discipline in managing their bankroll.
If your strategy says max 5% per stake, then stick to that. In the long run, if you hit more right than wrong, you’ll end up profitable. But those who suddenly increase their stake because they got carried away, that’s when emotions run the show instead of the mind.