Continue to invest/hold, and avoid selling, maybe this way the price of bitcoin can be as stable. But we cannot rely on this method if only done by ourselves because bitcoin is global. After all it's very contrary to popularity which's owned by bitcoin.
If everyone will only buy and keep Bitcoin, nothing good will come of it. It will only senselessly increase in price, that is, swell like a financial bubble. And this, sooner or later, will lead to the emergence of panic and its depreciation. This is the path to nowhere. We do not need to strive to increase the price of Bitcoin. It is necessary to develop his ability as a means of payment. It should grow in price due to turnover, and not due to its retention, that is, the reduction of supply in the market. If the bitcoin supply on the market is significantly reduced, people will simply switch to using another cryptocurrency.