Open access are not always free. I think one of the biggest materials science journal is asking from the authors to pay something in the order of $4,000 to make it open access [1].

The trick is to kick out out the for-profit middlemen who are taking advantage of the prestige and impact that various journals built over time, and now they just receive paychecks and free labor.

[1] https://authorservices.wiley.com/author-resources/Journal-Au...

Open Access journals carry significant fees in many fields.

Beyond that, the best journals in your field may not be open access. In my sub-specialty, none of them are.