The most probable scenario is that the gambler ends up even poorer than before.
But to prevent that from happening, you have to limit your balance for playing, that is, if you have little money, it is best to limit the money for playing and not commit all your money. Personally, that is my strategy, and once things work out, well, otherwise what can happen is that once you lose, you can leave everything there, not bet any more, and that is the most correct thing to do, but you have to have the necessary discipline to not deposit any more money.
Yes, that is one thing, and maybe I will also say another thing that should not be forgotten, the idea that you suggested regarding limiting the amount of betting balance I think will not be very helpful to limit unwanted things if from the beginning a gambler does not apply limits to their expectations of winning, meaning these are two things that must be combined to produce perfect prevention.
First, limiting hopes or expectations of winning and secondly limiting the amount of balance that is bet, and maybe I will say another thing that is no less important is self-acceptance regarding risk, because even if you have limits on winning and the amount of bet all of that can end up being useless when you are unable to accept the situation of losing, so those are three things that must be combined in your approach to gambling.