Some experience with this, but not a developer. Progressive disclosure is not in and of itself inaccessible; it's the way it's implemented. Be really careful with show and hide properties. One of my former teammates is visually impaired and we relied on him to test public-facing web apps. He found two big issues that made it impossible for him to proceed with a screen-reader, or even to parse the page logically. They can be corrected, but you'll need someone smarter than me to provide you with the fixes:
- Failure to associate radio button labels with radio button groups. This resulted in a series of questions with obvious "Yes" answers leading deeper into the flow, and any "No" answers ending the flow with a "Thanks for trying!" intercept page. The very last question's radio button group was unlabeled, so he figured the right answer was "Yes" and gamely moved on. Unfortunately, the question was "Have you ever been convicted of a felony?" and resulted in a hard stop with no explanation. Progressive disclosure fail; it required a "No" answer, but the question was completely hidden from the screen reader.
- Programmatically showing/hiding divs. Everything, but everything, was visible to the screen reader, making the page a hopeless jumble and throwing away all the conditionality (because he had access to things that were intended to be progressively disclosed).
I hope this is at least a start. Good for you for working towards accessibility.