DCA is also not for those who do not have stable finances, it is difficult to do DCA if your finances are not stable so I suggest you have a stable income first out there then you can do DCA happily without any obstacles.
It is very good to have a stable source of income but that mentality of saying that one must have a stable source of income before starting Bitcoin investment can be very wrong because with the dca strategy we can be accumulating Bitcoin whenever we have a discretionary income and at the time be working on our sources of income, it is wrong for us to see Bitcoin as burdensome investment such that we don't have to wait until our sources of income is stable before we can start buying Bitcoin and there is saying that a low coiner is better than a no coiner , one of the things I have learnt is that there are things that we can actually be working upon while we are at the same time buying Bitcoin without thinking that we must perfect in them before getting started and this includes our financial too, but we must accept and be working towards making an improvement.
Relying on your discretional income wouldn't be enough to sustain your investment, because the primary aim of any investor is sustainability of his investment, the ability to hodl for a long term and in other for you to achieve that, certain measures has to be put in place and one of this measure to be considered is having a stable source of income.
A stable source of income is very important for any investor who plans to sustain his investment and hodl for a longer term,having a stable source income will help you as an investor to set up an Emergency funds for your investment. An Emergency funds will aid you to take care of your financial emergency and unplanned expenses in the Sense you might not be tempted to tamper with your investment in the future. Remember the main aim is to Hodl for a long term,having considered and put this important measures in place,your plan to Hodl for a longer term is certain to be successful and achievable and your focus to consistently buying of bitcoin using DCA strategy will not be hindered.
I think you don't understand my point what I am saying is that having a stable source of income is very good but it is not a criteria that you must first have a stable source of income before one can start a Bitcoin investment, you can be accumulating Bitcoin with the little money you have so far is from your discretionary income while at the same time you will be working on your finances