As someone with friends who use screen readers, I notice when sites are close, but not quite there. Many websites are just a lost cause, but this is very close to very accessible :)
The main limitation is it would be nice if the sections were labelled, either with a <hx>, or <section>, to make it easier to jump around the page.
The ascii art gets read, which is a bit annoying, aria-hidden="true" will make the ascii art not get read out as text.
The best option is to try out with a screen reader -- on both windows + mac a decent screen reader is built in (it's worth best with the default browser, safari on mac, edge on windows). I'm not expert on screen reading on Linux.
This is something that frustrates me: it's actually really hard to design for screenreaders because it's hard to actually check the results in a free/volunteer context. So you often just have to just hope you're being "semantic" enough.
And I did try to use Orca but I just could not get it to work, the TTS service was sulkily disinclined to accept any requests.
Nowadays it's really easy to check on mac + windows, as the built in stuff is "good enough", particularly if you use the OSes default browser (Safari and edge respectively).
Do other users who depend on screen readers have an experience they’re willing to share about visiting this site?