Ouch. Don’t do that…
You might have more luck with the option driver. The qcserial driver has a strict layout built-in. But success will depend on the AT function still being enabled by firmware. And I’m not sure it is… Anyway, the option driver is worth a try. See the hints here: EM7565 wrong USBCOMP Command sent - did i brick it?
Don’t panic. Collect and post more information if you can’t figure out a way to get to a working AT command function.