There isn't a verse in the Bible that says "Thou shalt not gamble" or the equivalent thereof, so no, gambling isn't a SIN per se. However, it may be unwise (see Proverbs) or contribute to church disorder.
First of all, I would consider 1 Timothy 4:8: "But if anyone does not provide for his own, and especially for those of his household, he has denied the faith and is worse than an unbeliever." If you need the money for your household, don't gamble using it. If you do, that contributes to church disorder by forcing your household members to go to the church or other resources in order to eat. Don't place them in that position.
Second principle: "Wealth hastily gotten will dwindle, but those who gather little by little will increase it." from Proverbs 13:11. You've probably experienced this in your work picking stocks. What you are looking for is things (usually tech products) that the market undervalues that will go up to market value, increasing your hoard along with it. It's a job, and I'm glad you're treating it that way.
Third principle: 2 Thessalonians 3:10: "For even when we were with you, we gave you this command: anyone unwilling to work should not eat." So we can't use gambling (on stocks or otherwise) as a golden tunnel to get out of working. Having large amounts of money doesn't really get you out of working anyway, it just changes your work from earning money to managing it by investing it wisely. The verse from Ecclesiastes 11 quoted earlier makes that clear.
Finally, Proverbs 28:19: "Anyone who tills the land will have plenty of bread, but one who follows worthless pursuits will have plenty of poverty." If a gambling opportunity doesn't doesn't make a return, it's a worthless pursuit. We abandon those. We are called to be "shrewd as serpents and innocent as doves" (Matthew 10:16) and we definitely need that with our provision at stake.
The good news is that following these principles will actually increase your total profit from gambling. The bad news is that it will take longer to reach your financial goal than you probably want.
Principles of Christian Ethical Gambling
1. Set an amount that you are going to risk, and only risk that amount. NEVER risk your winnings.
2. Set the financial goal that you want to reach, and when you reach that goal, stop gambling.
3. If you lose the amount of money that you risk, you earn it back through working or another income source.
4. Place all winnings in high-yield savings accounts for inflation protection. NEVER use any gambling profits as risk money. That's a rookie mistake that can cause you to spend more than you intended.
How it works: Let's say I'm at a casino playing black jack, and I decide to risk $1000 on the game. I win $60,000 at that table, let's say. A rookie will take $60,000 to the next table and bet it all on the next game, hoping to double it. NOPE. WRONG. I cash out and I go to another casino across the street. At the second casino, I bet $1000 on the second game. Now let's say I lose the second game and lose $250 on that game. Then when I walk to the third table, what do I bet? $750. Maybe I win $20,000 on that third game. Doesn't matter. I'm still only going to bet $750 on the next game. I keep playing until I run out of risk money or I reach my financial goal. Using this method, the winnings are yours.
But let's consider another possibility. Let's say I won that $60,000 but I bet $1000 on the second game and lose all of it. Now in the terms of the gambler's day, this is not a desirable outcome, because I can't play anymore. Gambling games are FUN. Walking home, I'm going to feel miserable, replaying the loss in my head, and my mind doing mathematical justifications trying to regain $1000 to play another game.
But in the morning I'm going to wake up with $59,000, which is $59,000 more than the person who bet all of their winnings on the next game and never considered risk amounts.
How this applies to Stock Gambling:
Let's say I decide to risk $1000 on my way to $40,000. When the stock goes up, I sell my shares until I am down to $1000 in risk, and put that money away in a high-interest bank account or bond that hedges me against inflation. The gambling profit shall never be risked. I would take it out of there ASAP, though that's tricky because of share prices and calling times that can make selling down to a set amount difficult. If I get a winner, I keep on selling and taking the money and running. If I leave it in the system, I could lose it.
If I start losing money from $1000 - take it out - but I don't top it up. I go find another winner that's low. Keep playing until I run out of risk money. (If I want to play multiple stocks at once, that's fine, but I don't use that as an excuse to expand the risk pool. $250 to Stock A, $250 to Stock B, $500 to Stock C. Etc. And also I need to keep track of what I put in each one because if one goes up then I sell off back to the amount of risk I put in each one.)
I NEVER put my gambling profit back in the risk pool. Ever. That's how I lose it all or keep playing in blind hope. I do not let my emotions or dopamine control the game. Instead, I'm going to have to re-earn that $1000 from a real job or another source of income. When my designated HYSA marked "Gambling Profit" makes 40 grand, congratulations! Now I get whatever remaining risk money out of the game and put it back in checking. Whew!
Granted, this method is a LOT slower than the sloppy "risk it all" method, but it will give you the biggest profit over time. You'll start treating your gambling like a job instead of a thrill ride because every loss will be measured in work misery and every gain will just exist until the goal is reached. And is actually a job, researching companies to decide which ones to invest in and day trade. You seem to be good at it. If you follow the roadmap above you'll avoid the twin dangers of reaching deeper and deeper into your pocket chasing wins and also avoid losing huge amounts. The big danger is losing HUGE amounts that one can't afford to and then chasing wins to make it up, while not learning how to play the actual game. If you work for every risk, suddenly actually studying card counting or tech product market values may not seem like such a drag anymore. Because the more you win, the less you have to play, and the less you have to work to play.
How I learned this: Playing mobile game offers. If you look at Skillz type mobile games, those games are a scam because they FORCE all of the players to place their winnings in the same pool as their risk money. This eventually sucks all of the players dry and leaves NONE of them with any money - the house always wins. Playing mobile game offers has a gambling component to them because you're betting seed money on in-app purchases will get you to a certain level in-game for a certain payout, which is a bunch of principles based on development patterns for these games and complicated math.
I should point out that any sort of gambling requires mathematical intelligence in general to do effectively. If you don't have that and are emotionally sensitive, I think starting a blog or YouTube channel to earn the money is a more sensible alternative.
