I think you should try to limit the amount of money you use for gambling. Moreover, you said that you experience defeat more often.
Actually, this feeling of displeasure arises when your money is continuously eroded by losing at your own game.
If you can reduce the amount of money to the point where you feel fine, I think you will also feel happy when playing even though your potential winnings are small.
Many people enjoy gambling and find it fun because they are not at all bothered by the losses they incur, they just want to play honestly.
Honest gamblers are able to remain honest because they risk what they can afford to lose, your point is very accurate, gamblers can only become frustrated and unhappy when they keep losing everytime they use some money that in hope they want to make some more money back.
The only way a game can remain fun is you not expecting to get rich with your bets, you did it for the fun of it, and such money that's worth calling fun should be very little in amount, the type of money that you can give away to someone without feeling at thing.
I know this is probably hard for many gamblers, because they are into gambling to win some good amount of money and use that money to do something big, I myself decided to only gamble when I feel like and not make a job out of it because this is not why gambling existed, it's not a way to get rich or a source of income every day, understanding is all that many people failed to get about gambling.
When gambling becomes more than a hobby, you're setting yourself up to fail. Despite your advice to "only gamble what you can afford to lose," many gamble with money that was never supposed to be lost
They forget or never understand that the house always wins. The stark reality of probability and statistics is not cynicism. Casino gambling should be brief, not a desperate attempt to save money. You saw it clearly, a remarkable feat in a sea of delusion. I wish more people could appreciate the narrow boundary between a harmless flutter and a devastating storm. Understanding the game is more important than winning