Legally acceptable if the person it is signing on behalf of is aware of it's use and agrees to what is being signed.
If Biden did not know what he was approving and did not give his concurrence to those specific orders, they can be considered fraudulent and void.
If hackers accessed your computer, signed over your assets to themselves, and used your Adobe or Docusign or whatever credentials to do so, it is no different.
You weren't aware of what was signed. You / your actual beneficiary should expect it to be legally void.
And sorry, "hey we're signing the Pardons" / "okay whatever" is unacceptable coverage.
