Let us assume you invested $190 when bitcoin price was at $19000. The price of bitcoin presently is $21000. The asset worth from $19000 to $21000 is $210. The profit gained is $20. The percentage gained is still approximately 9.5%.
To buy at low price and sell at high price is good, but holding longer for monoths or like 2 or more years may earn more profit after bear market, instead of swing trading after long time of having your asset in fiat or stable coin.
But you forgot to consider that you can do multiple swing trade on the period of 2 months or 2 years on calculating the potential profit. The OP is actually right about his strategy, It’s simple and common but that is the best strategy on bear market like this since the price keeps dipping and correcting in short period of time and holding long term while there’s a clear sign for a long downtrend is just missing the opportunity to earn and increase your position before you hold for long term. You can always buy once there’s a confirmation of uptrend because you just missed some percent of profit compared to the person that buy the bottom but still swing traders has more profit in total due to there small trades during price swing.