Just don't forget that bitcoin's volatility is created mainly by derivative products and those traders who actively use leverage. The biggest provider of volatility for bitcoin is the derivatives markets. As the price increases, the use of borrowed funds will also increase. The fewer coins in circulation, the greater the volatility. I doubt that if bitcoin is worth $400,000, then the volatility will be lower than it is now. Exchanges will still draw the required trading volumes and will still provide unsecured derivative candy wrappers. Because if you have 1 BTC and decide to use 100 leverage, the exchange will lend you 100 bitcoins. You will make 1 buy and 1 sell, as a result, the trading volume will increase by 200 BTC for 1 trade, even if it is a short-term one. There is no way exchanges back those borrowed 100 bitcoins with physical bitcoins, it's all air, just numbers in the interface, but they affect the volatility and price of bitcoin.
As the volume of derivatives continues to grow, so will volatility, regardless of the value of bitcoin itself.