Would this render a phone’s flash memory unrecoverable?

Hi, I work in a field in which privacy and confidentiality are taken very seriously, and I plan to uphold that to the very best of my ability. I have an old phone (Samsung S21 Ultra) I used for work, and I’m trying to find the best way to render it completely unrecoverable. My current best plan has been to factory reset it and then take out the PCB with the flash memory and drill a hole through it, but …

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