error 9 and error 75

I have an iPad Air 2 that I was trying to update from ios 13 to ios 14. The update crashed and I'm in a feedback loop of trying to restore and/or update, but keep getting one of the following two errors: "The iPad “iPad” could not be updated. An unknown error occurred [9]" or "The iPad “iPad” could not be updated. An unknown error occurred [75]."

I've tried three different cables, 2 different macbooks, and the earphones-plugged-in trick. Nothing is working. I'm also unable to get DFU mode to engage. Please help! The ipad was in great working condition prior to this.