couple of articles for you to read, and I'm sure there are more (note that this is not a recommendation for either approach, just something to read so that you can make an informed choice). Whatever you choose to do, a simple delete *.* is not sufficient (but I think you know that already)
How to securely erase hard drives (HDDs) and solid state drives (SSDs) | ZDNet
https://www.pcworld.com/article/2617...ard_drive.html