What a roulette strategy that works would actually look like

The house edge comes from the payout table, not from the sequence of results. A straight-up on a 37-pocket wheel pays 35:1, which is what a 36-pocket wheel would justify. That shortfall of one pocket is 2.70% of every bet, on every spin, independent of every other spin. No ordering of bets, no pattern of stakes, no reading of the history board can alter it because none of those things touch the payout table or the number of pockets.

Progressive systems look like they work because they shift losses into rare events. Martingale wins most sessions. The sessions it loses cost more than all the wins combined. The sum is minus 2.70% of turnover, same as flat betting, with a worse worst case.

Choose French over European over American. Keep the stake small relative to the bankroll. Fix the spin count. These three decisions set the price of a session almost entirely, and they are the only strategy that changes the number at the bottom of a year's play.

If you want small, frequent wins and small, frequent losses, bet outside and flat. If you want a shot at a larger win while capping the downside at one unit per spin, Paroli. If you want the sector bets' smoother ride on numbers, Voisins or neighbours at a fixed chip count. Each of these shapes a session in a predictable way and none of them escalates after a loss. They "work" in the sense that they do what they say.

A stop-win and a stop-loss, set in advance and kept. A same-day withdrawal of anything won. A deposit limit on the account that matches the plan. These are behavioural, not mathematical, and they are where most of the real-world difference between players comes from.

Any system described as a sure thing, as "beating the casino" or "the house doesn't want you to know". Any software that predicts the next number. Any approach that requires increasing stakes after losses with no cap. Any strategy sold for money, because if it worked the seller would not need yours.

Single-zero table, French if available. Flat stakes of 1% to 2% of a session bankroll on outside bets, or half that on numbers. A spin count and a stop-win decided before the first chip. No increase after a loss. Withdraw on the way out. It is not exciting, and it costs about 2.70% of turnover. That is as good as roulette gets, and it is a reasonable price for an evening if the evening was the point.