This is not truly foolproof. Data can still be recovered from the spinning metal platter since it can theoretically be removed and put into a recovery device, even in a broken state.

Im addition to that, hard drives/ssd's sometimes have small flash memory chips, from which data can sometimes be recovered.

If you want it to actually be unrecoverable then you have to actually ensure all parts thay store data are truly deleted/wiped, which is more than just the core platter. Or just use encryption and throw away the key, since all data going through the tiny OS on these devices will be encrypted. Or just store them forever in a vault.