The 4th Amendment does not restrict the demands that one party in a transaction can make of the other. It doesn't comment on contracts between private parties at all.

Similarly, the 1st Amendment does not prevent victims of sexual abuse from signing a contract that forbids them from talking about it.

Both amendments are restrictions on government, not private entities.

However you cannot sign away you’re right to do so - I.e. you can sign the contract and then violate the contract and then nothing happens until someone sued you for breach of contract. The devil is in the details, though. Similarly you also can’t sign away your right to bear arms or sign yourself or children into slavery. Your wife can’t sign away her right to vote. Etc.

You can absolutely sign away your right to bear arms. Imagine, for example, a Disney star signing away her right to carry a machine gun into public places. You can sign away most of your rights.

You can't sign your children into slavery anymore in the US, but that's a special case that violates someone else's civil rights. Selling children and other people into slavery was legal for a big chunk of US history and was not fixed by the Constitution or the original Bill of Rights, but by the 13th Amendment.

You can’t sell yourself into slavery either. The Disney example isn’t a case of signing away rights. You can enter into agreements to do and not do certain things but your rights are not signed away. For example: you can sign a contract that says you’ll never say “Disney Sucks”. You can then go on the street and scream it at the top of your lungs. You’ll be sued by Disney for breaching a contract, but the status of your right to exercise freedom of speech has not changed. You won’t go to jail, for example. It’s not a criminal matter.

The government can take away your 1st and 2nd Amendment rights and you can go to jail for exercising them after that.

For example, judges can tell convicts not to buy or carry firearms.

The government can (arguably unconstitutionally) take away those rights after due process. KYC doesn't involve even probable cause a crime has occured.

Felon in possession laws are also laughably stupid and a horrible example of government tyranny. Someone who say illegally harvested or transported a lobster or had pot at the wrong time in the wrong state isn't less deserving of defending his family than the guy with a misdemeanor for DUI. I applaud any felon who continues to carry, knowing if they otherwise carry themselves honorably they are extremely unlikely to be caught conceal carrying. Thankfully projects like the fgc-9 3d-printed gun make it effectively impossible to stop felons from acquiring firearms and restores their 2nd amendment rights.

I was talking in the context of private entities. Though the government may be able to deprive convicted felons of certain rights (idk the details) it can’t deprive you of Constitutional rights (in theory). For the government to generally deprive someone of their rights it would be inherently unconstitutional. Obviously they can and do literally do this to people via edge cases they can’t do so legally - it would be a contradiction.