It’s funny, I was about to post a reply to help - but I looked up my answer (just to me sure), and it turns out I was wrong!

So I’m learning something here, too. Bookmarked so I can see what Spikes posts later

Arch Wiki has a rather decent article about wiping disks: https://wiki.archlinux.org/title/Securely_wipe_disk

Assuming your Pi runs a Linux distro, most of those tools should be already present on your system.