I will definitely do this and then, let my bank know that a large transaction is coming in so that my bank account will be put on hold for suspicious activity or money fraud.
I wouldn't do that. There is a chance that your bank won't do anything with your account when you receive such a large sum of money. Don't wake up sleeping dogs when you don't have to. I'm 100% sure that when you do notify them about a large incoming transfer, they will ask you to provide proof of source, which you claim to not be able to provide.
Don't shoot yourself in the foot.
I do have proof of source where the funds came from. The funds came from my Forex brokerage trading account. Forex a legitimate currency exchange market. I am sure the banks know what Forex is because banks also participate in the Forex market. Every time I withdraw funds from my Forex brokerage account, I keep copies of the transaction history.
It will vary on a particular country though yet i have experience when withdrawing out $10000 from my forex account to my bank account and the bank called me about on that specific
transaction and i do tell them the truth and they do release out those funds with just having that verbal confirmation on where those funds came from.
For that Coinbase matter, each account do have specific limitation when it comes to withdrawal and its risky to have that bulk transaction with them which chances of hold of funds would be high for sure
asking you out lots of documentation or sorts of verifications.