A very funny debate, how is it possible that when someone does DCA on bitcoin there must be a rule about the nominal, I think it is illogical. Because the name of the investment with the DCA method, of course it is up to each individual and no one should regulate how much money will be invested in each accumulation.
Nobody can control your finance and investment capital excepts if you make loan for investment and put your investment capital, personal finance at risk and sometimes on brink of bailout.
Because basically everyone's discretionary income will definitely be different, so of course the money that can be accumulated into bitcoin will definitely be different.
You only need to understand that centralized exchanges or centralized peer to peer marketplaces have their minimum trade sizes, that you must know and afford to meet it. Later you will have to meet its minimum withdrawal size so that you have clear ideas on how many times of DCA with a same small capital size for being allowed to withdraw your bitcoin.
It's also cost of withdrawal fee to make sure your withdrawal value is big enough to cover withdrawal fee to make the withdrawal fee on your withdrawal is not too expensive. If you make a withdrawal and withdrawal fee costs 50% or 70% of withdrawal value, it's too unwisely.