What’s the difference between a voluntary winding up and being struck off?

These are two distinct processes under the Companies Act, Chapter 386 of the Laws of Malta. A voluntary winding up is a formal process you actively initiate as the company's owner when you decide to close it down properly, which involves appointing a liquidator, settling all outstanding debts and obligations, distributing any remaining assets to shareholders, and formally dissolving the company at the end of the process, giving creditors and third parties a clear and orderly conclusion. Being struck off, by contrast, is generally something the Registrar does to a company, often as an enforcement measure for failing to file annual returns or other statutory documents over an extended period, and it does not necessarily deal properly with outstanding debts or assets, which can leave loose ends, such as the bank balance issue seen in cases where money is left stranded in a frozen account. Since you want to close the company down properly and your purpose has genuinely ended, a voluntary winding up is very likely the more appropriate and cleaner route, and it is worth engaging a licensed company service provider or lawyer to guide the liquidation process correctly.