I assume you're the author of that rant? I think you have one valid point:
Liquidity is king. If you have access to large amounts of money, you want to ensure the liquidity of a certain amount of that in various forms of crisis. Don't put it all in the same bank, don't put it all in banks, don't keep all of it digital. Having enough cash to bridge a temporary loss of access to your funds is probably a good idea the same way having enough potable water and non-perishable food at home to bridge a temporary infrastructure failure is a good idea.
The rest of the article however feels like a deepity[0]. Yes, your money isn't yours. But that's because there's no such a thing as "your money", or even "your anything" to begin with. Private property is a social construct, a mutually acknowledged fiction we turn into reality by abiding by it, under the threat of violence. Even gold has no intrinsic value, its value is entirely determined by what others are willing to give you in exchange and your ability to coerce them into doing so rather than simply taking it from you.
In other words, money is no different from any other "liberty" afforded to you by the state. Yes, the state can shut down your bank account but the state can also confiscate your physical cash (especially easily so in the US[1]). The state can even raid your home, put you under arrest or even kill you[2]. The Federal Reserve Bank may be a separate entity from the US government but it exists as the whim of the US government, as does CEDE and Company, which ultimately owns all stocks in the US.
If you think this is bad, you don't object banks, you object the state. And if you want to be ideologically consistent you should also object all corporations (which without the monopoly on violence of the state could only exist through private security, i.e. private militias, no different from feudal lordships in Europe prior to nationalism). This ultimately boils down to libertarian socialism ("free association"[3] being a key concept), though you strike me more as a right-libertarian type so Egoism[4] (not to be confused with "Egoismus" in German, which translated to "egotism" in English, i.e. self-obsession) might be an easier onramp to those ideas for you.
If you think that's going too far, I think you need to think more about the systems you exist within. The state can eradicate you at any moment and it doesn't even have to do so intentionally. There's no way to curtail the power of the state as any rights protected by it are only granted by itself unless there's a more powerful entity ruling over it (e.g. state vs federal law in the US).
On a more practical note, the situation you describe in your article seems to entirely boil down to not following the rules and then finding out there are consequences to that. There's a Process™ and you opted not to follow it out of willful ignorance. You clearly took the time to find out how to register a company but then opted not to find out what the steps to undo that are and offloaded your responsibility to the company handling payroll for you. Yes, this is hard to do yourself and yes, it's unfair that those millionaires you know can probably easily afford to just hire lawyers to take care of all these details without having to know of any of them, but that's pointing at a larger issue of structural preference for people who are already very wealthy. I'm with you on these legal tripwires being unfair because you're just supposed to know them or have the time to look them up (or even know what to look up) but it's just one of many ways in which the system punishes those who are not already in positions of wealth/power, even if it does so entirely without malice.
[0]: https://rationalwiki.org/wiki/Deepity
[1]: https://en.wikipedia.org/wiki/Civil_forfeiture_in_the_United...
[2]: Death penalty aside, law enforcement officers are rarely tried and found guilty for deaths, even in Germany. Infamously a Black immigrant died (either by being set on fire or prior to being set on fire) in a police holding cell in Germany a few years back. The original internal investigation was dropped and while the follow-up investigation in 2020 found evidence for "illegal" behavior from police officers, it found no justification to investigate any of the officers for murder or attempted murder.
[3]: https://en.wikipedia.org/wiki/Free_association_of_producers
[4]: https://en.wikipedia.org/wiki/Max_Stirner#Egoism