"All current Samsung phones come with an active regional lock when first bought. Assuming it's not also locked to a specific network, using a SIM from the same regional origin as the phone for at least 5 minutes of total talktime will disable the regional lock and allow you to use a SIM from any other region from then on."
If you contact Samsung Customer support from the region the phone was released in they might be able to remove this region lock remotely.
I wish you all the best with this situation.
Current Phone ~
Samsung Note 20 Ultra 5G SM-N9860_256Gb SnapDragon 865+
Samsung One Ui 3.1/ Android 11.
Hi, I had the same problem, but it is now resolved. I tried lots of different channels, none worked. What worked was this: I still have a European SIM card, so I asked someone in Europe to call me on my number for 5 minutes. It is now unlocked!