ok now the module is there!
ls /lib/modules/5.10.63-v7l+/kernel/sound/usb/line6/
modprobe snd-usb-line6
dmesg -w
(then plug the kb37):
[ 45.409460] usb 1-1.3: new full-speed USB device number 7 using dwc_otg
[ 45.583896] usb 1-1.3: New USB device found, idVendor=0e41, idProduct=4143, bcdDevice= 0.01
[ 45.583914] usb 1-1.3: New USB device strings: Mfr=1, Product=2, SerialNumber=0
[ 45.583922] usb 1-1.3: Product: TonePort KB37
[ 45.583928] usb 1-1.3: Manufacturer: Line 6