An invalidation level is a statement, not a number pulled from risk tolerance. If you are long because a swing-low held, the trade is invalidated by a close below that low. The stop goes there because that is where the idea dies.
Doing it this way separates two decisions that often get muddled: where the stop belongs, which the chart determines, and how large the position should be, which your risk-per-trade determines once the stop distance is known. See position-sizing.
The anti-pattern is choosing a stop distance first because it fits a desired position size, which places the stop inside noise and guarantees repeated small losses. If the correct invalidation is too far away for your account, the answer is a smaller position or no trade.
Related: trade-location, position-sizing, stop-loss, risk-per-trade, swing-low