If you can find a doctor that takes your ACA plan then anything other than checking for a pulse is likely to result in some sort of bill.
https://www.kff.org/report-section/2018-employer-health-bene...
And I have never had a doctor not accept an ACA compliant plan, which have been in the BCBS network for me.
This website seems to have a decent summary of coverage rules:
https://www.verywellhealth.com/aca-compliant-health-insuranc...
https://www.verywellhealth.com/preventive-care-whats-free-wh...
If your employer provided insurance it's good insurance, that's the perk of working there and part of your compensation.
If your employer doesn't provide it you have to buy during open enrollment through the exchange and the plans are terrible and expensive.
If you can find a doctor that takes your ACA plan then anything other than checking for a pulse is likely to result in some sort of bill.