Waiting and piling up the cash in fiat before you buy is totally the wrong approach if you ask me because Bitcoin isn't a stable coins and you can't expect the price to sit around and wait for you to gather all the money first before you now use when you are satisfied with the money for investment. The right thing to do is simply to keep striving to accumulate just like you have stated with the little earning so that you can meet up with atleast the lower price because you can't tell when the price might go up or even down.
That's right, collect cash first before buying Bitcoin, of course this is very wrong, we can skip buying when the price is down and it would be better if we continue to make purchases whenever we have funds that we can use to invest in Bitcoin and do it consistently in order to achieve satisfactory investment targets from the results of the investments we make.
But if you keep investing regularly using DCA method then you can invest monthly or weekly with your income or salary. So it only depends on the investor whether his investment is long term or short term, but Bitcoin investment is better to be long term. Because the longer the Bitcoin investment, the higher the benefits and the lower the risk.
I don't think waiting for the dip before accumulating Bitcoin as a good strategy, for there is no need waiting for the dip before accumulating Bitcoin as it is not necessary or important when buying using DCA method.
For me I see buying only when the market is DIP as trading. With your DCA strategy you can accumulate more Bitcoin regardless of the price either weekly or monthly as the case may be.