As a seller using an account that has your mobile number (like an opay account that removes the first zero in your number and uses as your bank account ) can be a mistake if you want to protect your privacy.
A buyer who already sees your mobile number displayed as your bank account don’t need to ask you for it anymore and many of them already jump into your dm without any permission sending you messages even though that they can just chat with you there on the exchange that is an attack on someone private space.
That’s not all you could be in more danger having your mobile number on an exchange
I quite understand what information you’re trying to pass OP from this thread, but one thing we need to let clear of is if you want to protect your privacy as you stated then you have absolutely nothing to do using a centralized exchange that requires KYC, once you have registered and provided KYC on platforms like this you can just be careful from there but there is nothing like privacy again. Phone details if not used for account details might be required during setup or you use your email which is still giving out personal information.
Phone number tricks are there but it requires more information to be added before the Scammer can be able to get you information, phone number can not be used to access your bank details even from fintechs banks except you actually give them access through token codes like OTP.
Although it is not bad actually using the number which isn’t serious attached to you but since you have BVN or NIN attached to exchanges you cannot be anonymous fully.
For fully anonymity you need to avoid KYC oriented exchanges