In order to find the one trading strategy that will bring the maximum profit, it is necessary to test many trading strategies. And even when you have found the only trading strategy that you think suits you, you should not focus on it, but continue to test new strategies.
I agree with you, only one strategy can never bring you consistent profits, because the market is changing, here you can never achieve consistent success by using only one strategy, so it is unreasonable to expect that any strategy will work forever. The strategy that brings you profit today, this strategy may cause you loss tomorrow, because today's market position will never match tomorrow's market situation. So it is not reasonable to think of ever achieving success with only one strategy.