Many contracts have illegal terms in them that explicitly also add durability clauses so that illegal terms in a jurisdiction are already thrown out but the rest of the contract stays.

That established, what business contracts are entered, executed, and completed ethically and with equal respect to the rights of the contracting parties? Very few, if any. In practice, the ability to enter a contract is the ability to go into moral debt and be slave to a document.

So no, I don't think contracts should be entered freely because most contracts are actually one-sided as fuck and generally have no room for negotiation.

If you don't think contracts should be entered into freely, then you have a problem with one of the core tenets of capitalism -- ownership of goods. I disagree with you, but capitalism has many flaws!

Indeed, I am against tenets of capitalism. It is a vehicle through which people commit exploitative acts and pass it off as merit. Money does not come from thin air, and profits to one entity means loss of value to another. Profit only comes when you charge more for something than it cost to produce or service, therefore the way to succeed in capitalism is to mislead, connive, haggle down where possible, and overcharge where possible. That's quite a list of moral hazards that, when cast out into an aggregate, results in social decay.

Ownership is also an illusion; government can confiscate anything it wants and there's no recourse. They can even take your home if the right boxes are checked. So how exactly is that tenet being respected?

On some level, yes, I see that there should be respect between an object someone works for and them. The issue is the value of each person's labor is completely subjective and up to the opinions of owners. There is no benefit to being working class, for example. There is only benefit for owners under capitalism, and even that gain comes at the cost of screwing over your neighbors.

It is not a system that can take the entirety of a human group and raise them up. It picks a handful, plays "Some of you May Die", shrugs, and leaves the citizens to themselves to fight over resources.

Freely enterable contracts mean one-sided contracts will be allowed. That's not a freedom worth protecting, because it invites exploitation. Just the same, allowing endless exclusive ownership means the owners control everything, and will create ways to block entry to their class or other efforts at equality. Capitalism does nothing to address its weaknesses, and were it not for extreme sacrifice from the working class and token placating acts of regulation from government, it could not function as a legitimate economy or way of life. It rewards the worst in humanity, and then has somehow convinced most of society that it's okay to fuck each other over.

My argument for sure collapses once you don't accept capitalism, so fair enough! There are problems with capitalism, and property ownership has a lot of downsides.