I was never privy to the true details but I suspect that they are making good use of torx screwdrivers and abrasives (wire brush, sandpaper, etc) right about now. It's slower but they have a fairly good amount of time to deal with it.

If they have time they're wiping things first.

You can also just burn them. It's not the Taliban they're worried about, it's the Russian and Chinese spies who will sneak in and pocket stuff, but that's mostly dealt with with policies that keep the kind of info those people would want off of hard drives in an unrelated nation.

Bending is generally considered safer, as it prevents rotating the drive, making any recovery attempts prohibitively slow and expensive.

Most defense contractor infosec departments will accept video evidence of HDD destruction so long as they do a walk through showing serial numbers so they know which drives are accounted for.

As a result there's tons of videos that the public will never see of the world's heaviest presses, shears and brakes being used to decimate lines of hard drives. When you run a shipyard it's cheaper to just bend hard drives than it is to ship them back to HQ and have infosec deal with them.

One of my jobs as an intern was to take a list of serial numbers and watch the video walk-through and confirm the list matched the drives.

Is the substrate glass? Does it shatter when you drill the hole? If so, drilling might be fairly good.

It's a mix according to https://en.wikipedia.org/wiki/Hard_disk_drive_platter

depending how you're doing it, it's actually quite difficult to properly drill a hard drive.