I did just find an intriguing ePub3-compatible reader -- with MathML support! -- which is open-source, cross-platform (Windows/macos/Linux) and specific about maintaining non-visual access.
Thorium descends from a Chrome extension, Readium, which Chrome no longer supports.
Running it on my laptop in macOS Catalina. Very basic -- does support copy, but not highlight, yet. Very actively in development. Will keep my eyes peeled, so to speak.
Re: Pass the wine
https://www.edrlab.org/software/thorium-reader/
Thorium descends from a Chrome extension, Readium, which Chrome no longer supports.
Running it on my laptop in macOS Catalina. Very basic -- does support copy, but not highlight, yet. Very actively in development. Will keep my eyes peeled, so to speak.