[ta1748]

This is the easiest way to get an idea for what is happening and what experience is needed:

https://jobs.apple.com/en-us/search?search=formal&sort=relev...

There are several different niches, and HW formal is likely using different tools and methods than SW formal, though there is overlap. Anyways there is room for a wide range of experience/skills/background in a variety of different areas.