Llyr Williams's Beethoven sonata cycle, one of the most extraordinary feats of musicianship in our still new century, had been scheduled at the Guadalajara, Mexico, music festival in 2020 as part of the composer's 250th anniversary celebration. The series was deferred, however, because of the pandemic. (It looks as though the series will appear at last in Guadalajara in May 2024. Follow the artist's website for futur…