Any strategy that you decide to adopt for your Bitcoin investment is your choice inasmuch as you are increasing your stash.
Seems you're getting it right already, because the purpose for any investment made was to have that opportunity of building up our portfolio, which is why we should not take from the investment fund we have because such is our capital, the more it remains being invested the better it becomes for us, as we know already that bitcoin increases over time, despite its volatility, at the long run, we still stand a better chance of earning more form it as long as we can hodl.
Currently, Bitcoin has the most modern DCA method of investing, whenever you decide to invest in Bitcoin, you cannot immediately withdraw money from your investment. For this reason, a designated hardware wallet is necessary for every Bitcoin holder because it is not possible to easily withdraw Bitcoin from a hardware wallet.
However, I think it is most reasonable for the investor to collect emergency funds, because if there is an emergency fund, it will be easier to control money properly and continue investing according to the DCA method. A person can allocate money for Bitcoin investment depending on his income, but no matter what the situation, it is most important to follow the DCA method regularly.