If they already push and test 14.1, the last 14.0 Beta is probably what ships with iOS 14. That's the same scenario as last year with iOS 13 Beta 8 being the GM build (mid August?) with them pushing 13.1 Beta 1 instead of 13.0 Beta 8 (and a few more betas, before the keynote).
Yeah I got that too-this year is the first time we have HomePod betas through AppleSeed. I think they barely need us to test the OS and that’s why testing for audioOS 14 has already ended and they’re now on to 14.1.