Iphone 16 Pro Max - Bluetooth connection failure, device is "blind"

New Iphone 16 Pro max copied from perfectly working 12 Pro Max device.

After 2 days, device lost connection to all Bluetooth devices (including apple watch, headphones, car, more).

Reading forum recommendations and actions taken:

1. Trying to shut off / on Bluetooth - didn't help.
2. Trying to move to flight mode and back - didn't work.
3. Trying to forget devices and reconnect - didn't work.
4. Full device restart - immediately all connections restored but, 2 days later (after 2nd night charge) - all Bluetooth connection lost.
5. Network reset - same result as device reboot (had to add passwords where applicable).
6. Software upgrade to 18.2 - didn't solve this issue, same result.

All above tests were done while my older Iphone 12 Pro Max was shut off,

While 16 Pro Max disconnected from Bluetooth, restart and checking again with my older 12 Pro Max - all Bluetooth devices were immediately connected while the 16 Pro Max stays "blind".

All in all,

When it works no issue, when disconnected (after 2nd night charge), nothing helps other than device restart of network reset.

Appreciate community advice - is it hardware issue and I need to turn the phone back to store or, there is any other software setup action which can resolve this matter. Tnx.