I figured this out in the end, but I’m posting this in case anyone has a similar problem on the 16:
The bluetooth signal between my 16 and headphones randomly cut out, and the bluetooth button disappeared from the control menu, along with the settings page for bluetooth connections. Checking device manager, the bluetooth section had disappeared as well, and there was a new USB driver that had an error labelled “device descriptor check failed”.
Checked the forum, and found a similar issue on the 13 when people updated drivers or bios, and first tried to reinstall drivers, uninstalling the faulty USB one first, then restarting.
Then found that some people reported VPN conflicts with their bluetooth drivers, and uninstalled my VPN application. Repated the driver reinstallation process, still no luck.
Finally read someone’s suggestion to uninstall the faulty USB driver, reboot in bios, disconnect the battery from there, then restart. This fixed it.