The only strategy that will fit your situation now as a person who lacks fund is the lump sum method. This means you can only invest once at ago when you get fun or bonus from anywhere. But if you have a good income source then I will have sudgested the DCA method.
I am curious how someone that lacks funds will be able to invest in Bitcoin through the Lump sum, lump sum buying has a lot to do with buying a very huge amount and that is why it is preferable that those who don't have enough money to lump sum uses the dca method to buy Bitcoin with their financial strength, you also need to understand that the validation of DCA doesn't mean it must be from a stable income, the advice about it's consistency is to enable an investor to increase the size of their holding over time, if anyone is buying Bitcoin infrequently little by little it can still be called DCA
and not Lump sum.