Who multiplies bitcoin and how?

Here are the bitcoins on cold wallets.I'm thinking about how to multiply them safely?there's no way they'remultiply. The course has recently been going down. At first it bothered me a lot, but now it doesn't. Previously, my strategy was “buy at a lower price, but sell at a higher price and go to the cache”. But lately, more and more I have been thinking about not to get out of the cue ball, but to increase it. At price hikes, there are risks of losing capital. And already there was something that was losing.
In fact, this is a financial instrumentfrom which you can not leave, but make a monthly margin on it.
I will be very grateful if you share your secrets and strategies for multiplying Bitcoin.