Feel free to seek the advice of an attorney on taking the 5th on a tax form, but I suspect that will cause the IRS to do the necessary investigative work to obtain a warrant for your now extremely interesting tax return!
The answer is much simpler: being asked if you own or owned digital assets during a particular tax year doesn't amount to compelled admission of a crime, because owning digital assets isn't illegal. The only illegal thing would be dodging one's taxes.
[1]: https://www.irs.gov/publications/p525#en_US_2021_publink1000...
If that’s correct then I don’t see how you would be able to plead the 5th on a standard government form.
Similarly for a government form: the government can't slide you a piece of paper and compel you to bear witness against yourself outside of a courtroom. But that isn't remotely close to what's happening here, because none of the information the IRS asks taxpayers for can be used to prosecute them (because it isn't illegal to own digital assets).
Edit: s/ask/compel/
> Feel free to seek the advice of an attorney
> seek the advice of an attorney
> an attorney
Are you an attorney?
> being asked XXXX doesn't amount to compelled admission of a crime, because XXXX isn't illegal
This is bad legal advice! Talk to a lawyer (before you talk to the IRS or any government investigatory agency), especially if it is your plan or intent to lie to the government or challenge their interpretation of a law and how it governs your behavior (the premise of OP).
Better advice: Seek tax or legal advice on HN. From anyone.