Hello!
AudioTech wireless headset and it's telling me that it needs Bluetooth Encryption?
Strange thing to say about a headset. Maybe they're advertised as secure for no reason. (Unless it uses a more secure method below for pairing. Only the pairing procedure is susceptible to MITM)
Every phone and device utilizes bluetooth encryption.
Encryption was added in about 20 years ago.
The more secure BT connections are: compare a code on both devices, see a code on 1 device & type it in on the other, or connect another way like tap or QR code.
You can't change a setting to disable encryption or get better encryption. Every current pixel device that's not so old it is end-of-life will support all of these.
Just pair it to anything you'd like and the encryption is done for you. :)