Indeed, the Web Content Accessibility Guidelines explicitly allow creating a separate accessible version of content and linking to it. They call it a "conforming alternate version": https://www.w3.org/TR/2016/NOTE-WCAG20-TECHS-20161007/G190
(The guidelines say it's preferred for everything to conform directly, but they use "artistic integrity" as an example of a situation where a conforming alternate version could be used. I'd say that applies here.)
(The guidelines say it's preferred for everything to conform directly, but they use "artistic integrity" as an example of a situation where a conforming alternate version could be used. I'd say that applies here.)