It’s not entirely true. Bitcoin price is volatile so you can have profit as quickly as 1 day or shorter if you manage to purchase Bitcoin right before the price rally started.
It’s not necessarily true that you will only have profit on Bitcoin when holding long term while in fact Bitcoin price pump happened in spread time frame which means you can gain profit regardless how long or short you hold.
Basically, the point is that we should never look at the price of Bitcoin and should always continue to buy. If you think that the price of Bitcoin has increased a lot, then you can never invest, so it is never right to look at the price of Bitcoin.
You're right when you said that we shouldn't look at the price, because if you keep considering the price of bitcoin before getting started is either you will be afriad or feel disappointed as you will be making imaginations on how you will be able to achieve your investment goal now that the price of bitcoin have gone this far. This is what you will be thinking, and this can probably make you lose interest in bitcoin investment. So whoever that is ready to go into bitcoin investment need to pay less attention to the market condition but to keep buying with the DCA method, with time you will definitely reach your investment goal.
There is no guarantee that you will make a profit if you invest in Bitcoin. There are many risks in Bitcoin investment, but long-term investment is much less risky than short-term investment. If you can hold your saved Bitcoin for a long time, then you can make a profit.
Even though there is no guarantee that you will make profit if you invest in bitcoin, you need to ensure that you're doing the right thing, I mean let your focus be in the long term profit and see how it goes. Because those who are patient enough to HODL thier bitcoin in the long run didn't complain about any risk, instead they were testifying on how they made a huge profit from thier bitcoin investment so whoever that focus on the long term goal will never regret it.