Unfortunately, while many people believe this to be true -- there is nothing legally or morally wrong with you purchasing software from a small Russian or Iranian software developer. How do we know this, you ask?

In fact, the entire Open Source (and most Closed Source) stacks depend on this fact, including the stacks underlying the entire US Government's (and its Military's) operations. Which functions on large amounts of software (free and paid) from Russian individual developers.

So, any demand by them (or any other government) that you personally cannot pay Yegor the Russian for his little Python package is morally, logically, legally and practically ridiculous.

And "DeFi" absolutely does solve this problem.

The fact that "all the baaaad people" can also use "DeFi" is immaterial. Just like you, too, can buy and use a windowless white van.