It may be possible to manually slipstream the required audio drivers into the Windows installation package, but this is outside the scope of this comment. However, it may, as others pointed out, be possible to receive audio by plugging in a compatible USB sound card, but I have not tested this setup and thus cannot make a definitive statement regarding its viability. I have confirmed this to be true on the most recent Mac Mini model (released in 2018), the most recent 16-inch MacBook Pro model (released in 2019), and even several 15-inch MacBooK Pro models (from 2010, 2013, and 2015) all use similar audio chipsets that are not natively supported by the limited subset of drivers available during a Windows installation, and thus plugging 3.5mm headphones or speakers into any of these machines and attempting to start Narrator during the installation process results in the same thing: absolutely no sound. Thus, plugging in 3.5mm headphones will not enable support for Narrator during the initial Windows installation process, as has been the case now for quite a few years. I am a software developer familiar with both Windows and macOS, and can definitively confirm that the Boot Camp audio drivers are not slipstreamed into the Windows installation process that is started via the Boot Camp Assistant. Unfortunately, the information in your comment regarding audio support for 3.5mm headphone connections is factually inaccurate.

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