I think I've read all the posts on this topic. I've updated my case, tried with my iPhone 11 Max Plus (running latest IOS), iPad Pro (ditto) and my husband's iPhone 5 (running an 11 version of IOS). I've turned bluetooth on and off, turned airplane mode on and off, restarted my devices, deleted and re-downloaded the Bose Sleep app, and done combos of the above. No matter what I do, the Sleep app shows "searching nearby" and then "We're still looking for your sleep buds." Removing them from the case and putting them back in doesn't work either.
What the heck? Why can't I connect them to any device? I am very sorry now that I didn't send them back to Bose by the end of 2019. Though I never got any notification about the recall.