I doubt that being in bitcoin for 4-5 years or more helps you to know better when the BTC price will move,
There is nothing to be unsure of. It is a fact. Many years of experience cannot make an investor know what the price of bitcoin would be. Although experiences matters a lot when you want to accumulate Bitcoin. It will help you know the strategy to use and when to utilize that strategy to accumulate enough Bitcoin. In my experience DCA is the way. When it goes up we DCA and when it goes down we DCA as well. DCA has helped me neglect the urges to trade short term and sell often. With time it will be the best way to accumulate Bitcoin.
To catch up I have been involved with Bitcoin for a long time and I have witnessed many changes in the market and I understand the charts well but I can never be sure how the market will go in the future. By observing the chart, one can get some idea about the market that the market will form support and stop at resistance, but it cannot be sure which direction the market will go. In trading I usually adopt this kind of strategy and by adopting this kind of strategy I can get some success in trading but in investing I never pay much attention to the chart or market condition.
Long term investment means I have to buy and hold a particular coin for a long period of time and the market will change multiple times during this long period where charts will not be very useful. Skill and experience is required in investment because skill and experience in investment can hold the investment for a long time but investing in long term plan there other strategies are not very useful. A strategy that comes in handy for long-term investing is the DCA method of investing.
Investing in the DCA method sees bitcoins being purchased at each step, making the investment sound but with much less risk. Those who once did not understand the DCA method now find the DCA method to be the best investment strategy. It is always a good decision for an investor to start investing with the available amount and later invest in DCA method.
Good thing is you have understand how everything works with your years of experience. However, based on your narrative you sound like someone who is into day to day trading more than investing. You can only adopt DCA strategy when your investing not when your trading. Which means you have to give more priorities to how you invest and accumulate your bitcoin. Am sure you don't want to DCA for some period and later lose them to trading. Then what it is the essence of accumulating when your trading.
Also, not because majority of bitcoin investor have adopted DCA strategy then you have to say other method are bot very useful. Before DCA become popular there were other other method which have worked for many investor. One of which i know is the lump sum. When bitcoin started gaining big rise, Investors would wait for the price to go down and when it does they go all in the market. And back then the price was more affordable when the price has not exceed $10,000. A lot of persons where doing lump sum. Now the price is way high for a regular citizen to afford to buy once this is why the DCA method is adopted by many.