thinking bitcoin reaches $100k is something very realistic because as you said before, before the halving started the price of bitcoin had already reached $70k. However reality says otherwise because approaching the halving, Bitcoin prices tend to move down. Don't be discouraged, keep holding onto the Bitcoin you have because the opportunity to reach $100k is still wide open.
Bitcoin price must touch 100 as it is only a matter of time, as we are in the current halving it will touch together in time. The all-time high Bitcoin touched was 73.6, so the falling Bitcoin price has created an opportunity for investors to invest.
Yes you are right, when bitcoin price goes down it creates opportunities for investors to invest. While the price of Bitcoin is still low, there are still opportunities for those who haven't invested. But you can profit by investing at any time, for this you need to be patient and have the ability to hold for a long time. So one should continue to invest in DCA method instead of waiting for the market to decline.
Bitcoin's fourth halving has already been completed. After the halving the market started to pick up a bit, today the price of Bitcoin is around 65k. Now have to wait for bull run, hope bitcoin will cross 100k in bull run. Some expect Bitcoin to hit 150-200k in a bull run. If one does not want to regret the bull run then start investing now.