Hold on…. You’re saying I can take out a loan for $x amount of dollars against a company I don’t own yet and buy it with that money?

Yes

I take out a mortgage for a property before I buy it and I destroy the house; the bank still comes after me for the value.

Not the same, a house can't be a legal person, the owner is the legal person of the house. The money Musk borrowed in twitter is owed by twitter, not by Musk. To do the same with a house, you need to do it through a company.

That is possible because companies can have limited financial responsibility, meaning the money they owe are not owed by their owners.

It's a pretty nifty arrangement, to help the rich stay rich no matter what happens.

Am I being stupid or is the game more rigged than I thought?

We are stupid for not being rich enough, and still allowing the rich unfair advantages.