The barcode scanner app I use has a “Continuous Scan” mode where it will save the barcodes immediately and allow you to continue scanning - you could look for a barcode app on with this feature for whatever device you’re using to scan
Buy a barcode scanner. They are only as fast as you can scan things unless you want to build a machine that you put stacks of books into and it scans them for you…but you’d still need a barcode scanner.
Bunch of wireless barcode scanners on Amazon but it looks like all they do is scan the barcode and dump the value to your device, there’s no product lookup or anything like that.