Your entry isn't at the discretion of an IO, there are laws everyone on both sides have to follow. If an immigration office wants to refuse you entry, there must be a legal basis to do so. Entering Thailand often isn't a legal basis to refuse someone entry.
No, you cannot go to an ATM and withdraw money from your CD. You have to go to the bank and close the CD. Just like a stock, bond, or ETH. You have to sell the asset/investment before you can access the money. Fixed term deposit accounts cannot be used