My iPad Pro 10.5" 64GB also got "killed" by attempting to iPadOS - attempting the OTA update it crashed half way through, went black and didn't turn back on, I can't even install it via DFU mode. The only thing that revives it is restoring to 12.4.1.
To revive it, I entered DFU mode by connecting the iPad to a PC with iTunes, holding home and power for around 4 seconds, then releasing power while keeping home held until iTunes recognises it, and then restore to 12.4.1 (the restore to 13.1 still didn't work and resulted in an error). This is, to my knowledge, the only way to bring the iPad back from this state.
This definitely isn't an isolated incident! I really hope Apple takes notice and patches whatever is causing this, I know of at least 3 other people who've had this happen to them. The software update doesn't "kill" the iPad, but it definitely does not work properly and then requires a full restore.