Would love to hear how it goes! Miri is generally single-threaded, but because nextest is process-per-test, each test gets a completely separate Miri context. A few projects have switched their Miri runs over to nextest and are seeing dramatic improvements in CI times, e.g. [1].

[1] https://bsky.app/profile/lukaswirth.bsky.social/post/3lkg2sl...