I think the diagram from you it's quite simple and easy to understand, Your illustration is just quite educating to me, and also it quite simply illustrates everything that is being discussed in other thrends.
1. Your Income. From your income then you get
i. Essential Expenses, that is our bills,
ii. Discretionary income, which you still that that from your income.
iii. Emergency funds, reserve , floating funds which all still Comes from Income.
iv. Bitcoin Accumulation, which comes from our Discretionary income.
I believe this is quite simple and easy to understand from your diagram illustration.
You've perfectly expressed my perspective and POV in your own way and I'll say you've done justice to it. Everything, from your expenses to the discretionary income comes from your income, and none comes from the discretionary income, except accumulation of Bitcoin and a few bucks that may likely carry you to your next paycheck, every other expenses having been covered by your total income, and it is what's left after covering every other crucial expenses that is addressed as the discretionary income, that's what you'll choose to invest or buy your sats with. Although the percentage of the discretionary income one chooses to use in buying Bitcoin totally depends on how aggressive the investor decides to be, some decide to be super aggressive by investing 100% of their discretionary income (which I wouldn't advice though) and some choose to invest a lesser percentage so they can still have some change to carry them to their next paycheck.