As long as the price of cryptocurrency will depend on supply and demand, the high price volatility of cryptocurrency will remain. Still think the ETF funds can solve this problem, or at least will lessen the volatility of Bitcoin. The more control of the market, the less volatility it will be, now we still don't have any rule or laws to govern this market,.
Bitcoin don't need any rules to govern it's market, because this coin has always been the same from day one, and don' intend changing anytime soon. Because it is this volatility that makes Bitcoin unique from any other digital currency controlled by central banks and the government. So if you are not okay with it's volatility, it's best you invest in stable coins such as USDT or BUSD which are pegged to the United State dollar.