Solved: JBL Flip 4 and M1 Mac
M1 Mac connects bluetooth to the Flip 4 speaker, but it doesn't show up in the list of sound devices you could choose (airplay).
Solution for me was to use the JBL Portable App and turn on "speakerphone" mode. Then you have two devices in the bluetooth list, one identified as speaker and one not identified. But it then appears in the sound listings. Apparently if you don't do this, it doesn't register as a speaker.
BTW, don't download the JBL Headphone and Speaker app. It's a scam. They got my credit card. 😡
MacBook Air (M1, 2020)