The ACA does not require all private plans to cover preexisting conditions. It requires all marketplace exchange and ACA compliant plans to do so. But many insurers - including Blue Cross Blue Shied and UHC - withdrew from the healthcare.gov exchange years ago to sell non-ACA compliant plans instead. With the death of the individual mandate, they lost the insured numbers to make it work. The remaining plans there are from companies like Oscar and are frankly not competitive with what you can get separately - other than preexisting coverage.

Yes you can buy family plans, and of course it scales in price. Averages out to about $400 per person, but of course that also depends on the PPO list, copay v coinsurance, coverage for ancillary services like mental health and prescription medication, and etc.

Not all private health plans cover routine preventive care at a reduced rate. I was on a UHC plan where my annual checkup cost me several hundred dollars.

The ACA was awesome at first. It dramatically improved my personal health insurance. But within a couple of years, the exchange in my area was a ghost town. It is a shell now.