I would like to warn you at the beginning that you should never be sure or guaranteed about investing. It is certainly good to have faith in Bitcoin and our confidence in long-term investment, but it should not be blind faith or overconfidence. We expect Bitcoin to have a bright future in the long term and I think this hope is reasonable. So in the long term, Bitcoin is always bullish and we expect the price difference after 8-10 years to be much higher. But it is not guaranteed.
It is good to have a positive attitude towards Bitcoin and it may be best to engage in long-term investment with a positive attitude. In short-term investment, you will have to count losses or suffer from disappointment at some point. Even in real life, due to mental instability, that effect can disrupt your life. There is no such negative effect with DCA in long-term investment. Just make sure you invest with prudent money and invest to achieve your goals without setting a time limit.