As an older person I’d like to suggest another possibility:
it’s a hearing aid.
Some are very small and inconspicuous for those who want to avoid the associated stigma of “being hard of hearing and old.”
I wish I could see the top of hear ear. There are models with some electronics both in the ear and behind the ear. There is a small, almost invisible, arm which connects the behind-the-ear electronics to the in-the-ear device. I wear such a model, not cause I’m vain, but like the open ear design which improve the full range of hearing. My hearing loss is in a selective range, as for many who suffer hearing impairment.
Good point!
I’m severely hearing imoaired, so can relate to what you said.
And some hearing aids have Bluetooth capability; I will have to check the reception range.