Yes, there are several and more flexible ways you can accomplish tax deferral like a 401k.
Yes, it can involve corporations created in a United State or a different Nation state, or a state within a different nation state (some countries have nation level incorporation like the Cayman Islands, some have state level incorporation like the United States, some have state level and nation level incorporation statutes like St Kitts & Nevis).
Your plan though has bad assumptions and is flawed. You can ignore the answer about the costs of finding a tax professional, you can get brand new legal consultation and entity setups in multiple countries for less than $10,000, after you have decided which countries.
A) Corporations owned by American citizens have as much trouble getting a foreign bank account as an American citizen.
Counterpoint A) Offshore Corporations don't need bank accounts. See if you can structure your business to either be simply a holding company of assets, or if your business can get payments solely in cryptocurrency. You pay tax on whatever it transfers to you domestically, so you can cash out your crypto in US institutions when it pays you. Or your entity can just transact internationally for the things you really want. Its just an accounting gimmick at this point, since cryptocurrency wallets are property that you have to merely label as being part of one entity or your personal balance sheet. This remains an accurate capability no matter what anyone told you about cryptocurrency.
B) American beneficial owners of foreign bank accounts have to report FBAR. Foreign Banks are required to snitch on you due to FATCA, despite their country's own laws and constitutions because the country's sold out their sovereignty in the FATCA treaty with the United States. This is why foreign banks don't want to deal with Americans.
Counterpoint B) Offshore Corporations can have US bank accounts without creating tax liability. Big banks are typically confused at how to do it, especially when the beneficial owner is an American citizen. Boutique banks will just appreciate the business. Shop around. US Banks are not subject to FBAR. US territories are where the real gems are, because of their familiarity and proximity to foreign countries.
Also, cryptocurrencies holdings are not subject to FBAR. Reiterated by 2019 US Treasury and FinCEN guidance. But it wasn't ever really unclear.
C) US Taxes still applicable, but different ones: A US citizen beneficial owner of a foreign corporation has to consider Treasury and IRS regulations on Subpart F income, of which there are MANY exception, Controlled Foreign Corporations (CFC), and Passive Foreign Investment Companies (PFIC). Often times the result is still WAAAAAY lower than US income taxes, and you can basically ignore the states on this one, but it depends on which state.
D) Discretion. So yes, at the strictest interpretation taxes still apply, and the banks themselves will snitch, the countries are often in agreements to snitch on you, and your own compliance has the effect of telling the US government how much there is to tax. But you aren't inaccurate in your observation that beneficial ownership doesn't have to be known. There is just huge liability for you if it 1) becomes known 2) the US government disagrees with your tax deferral and compliance.
so thats the topic of foreign corporations. these are usually more useful for everything EXCEPT not paying taxes to the US government. So if you want to stall creditors, grifters, transact in privacy as a matter of trade secrets, and do crafty things with the price of assets that are owned, foreign corporations are pretty golden.
back to the root of your question, consider 501(c)(3) private foundations. But not for income, it has to grow on its own from income you have donated to it. But you can deduct 30-60% of your income to them. So thats way better than 401ks. It isn't NECESSARILY a tax deferral, but probably will be if you need to pay yourself.
Also consider moving to Puerto Rico. Many US entrepreneurs move there for Act 20 and Act 22, since there is an exemption on capital gains and income taxes. And you still get the US flag and institution. It isn't a tax deferral. But people typically go there for 1 year to cash out of large capital gains tax free, not to actually make a living like it seems like you need to do, but thats possible too if your commerce is mostly online.