Looks like BNO085 are in stock on Adafruit site.
They had a shipment of 497 come in October 4th. There are 121 left today.
315 currently in stock at digikey too… typical, you wait months for one, then two places in stock at once
Mouser have 779 in stock.
Bno085 at mouser.ca
No more BNO085 shortage, at least for north America.
But Teensy are hard to find now