The thing you're trying to do - sign up for insurance to cover a specific procedure - is quite literally what the system is designed to prevent. You're supposed to have insurance all the time or none of the time. Did you try asking the clinic how much it would cost if you are uninsured and paid cash?
Sorry I'm struggling to follow here. You think the open enrollment period effectively means that there's no prohibition on pre-existing conditions? Think you're kind of bending words outside of their normal usage because quite literally pre-existing condition policies are banned. The compensating counterbalance is a neutral open enrollment period so people don't just jump when they learn they have a health problem, it's a compromise to ensure financial sustainability.
You do understand that before this, it was worse right? One comment after another here is comparing the ACA to a magical fantasy, rather than the status quo that it improved upon.