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 low and sell high is good, but holding longer after time may earn more profit, instead of swing trading after long time of having your asset in fiat or stable coin.