You can use a nand programmer p13 from JC for example and put a compatible nand in the programmer and format nand for a ipad air 3 and write/unbind wifi. Then solder Nand back on to Ipad and update firmware in dfu mode.
Try to activate the device over wifi and you will not bypass activation.
Remove nand from ipad and put it in nand programmer again and QueryCode//Unbind and choose fast mode. Wait untill process is done and you have the old serial wifi and bluetooth.