I think I've read several times that BT pairing for Shearwater devices in Subsurface works for some devices while for others it doesn't - it's kind of random thing.
I recently bought a Peregrine too.
My mobile (Xiaomi Note 9 running Android) sees it but fails to pair with it.
My PC (dual boot with Windows 11 and Linux) using an old noname BT dongle sees the Peregrine but fails to pair with it. Just in case I bought a newer BT dongle and with it Subsurface in Linux pairs with the Peregrine(!) but Windows 11 still can't pair with it.
I also tried an Android tablet my kids are using and with it it works flawlessly.
Go figure
I recently bought a Peregrine too.
My mobile (Xiaomi Note 9 running Android) sees it but fails to pair with it.
My PC (dual boot with Windows 11 and Linux) using an old noname BT dongle sees the Peregrine but fails to pair with it. Just in case I bought a newer BT dongle and with it Subsurface in Linux pairs with the Peregrine(!) but Windows 11 still can't pair with it.
I also tried an Android tablet my kids are using and with it it works flawlessly.
Go figure