How to permanently delete files so they can't be recovered

A reset is enough on an SSD as long as you pick the right option. Settings, System, Recovery, Reset this PC, Remove everything, and on the additional settings step click Change settings and turn on Clean data. That's the full wipe rather than the quick one. Old school overwrite tools like DBAN are actually a bad idea on an SSD, wear levelling means they don't reach every cell and they burn write cycles for nothing. And if the laptop had device encryption or BitLocker on, the reset throws away the key, so anything left behind is unreadable anyway.