Multiple Errors while trying to get a live Kali usb on my system

I am trying to get kali to run as a virtual usb on my manjaro system following the steps from this guide https://github.com/nkpro2000sr/man-manjaro/blob/master/AlsoKali.md and everything worked up until tried to update grub where this happened

Generating grub configuration file …
Found theme: /usr/share/grub/themes/manjaro/theme.txt
Found linux image: /boot/vmlinuz-6.1-x86_64
Found initrd image: /boot/intel-ucode.img /boot/initramfs-6.1-x86_64.img
Found initrd fallback image: /boot/initramfs-6.1-x86_64-fallback.img
Found linux image: /boot/vmlinuz-4.19-x86_64
Found initrd image: /boot/intel-ucode.img /boot/initramfs-4.19-x86_64.img
Found initrd fallback image: /boot/initramfs-4.19-x86_64-fallback.img
Warning: os-prober will be executed to detect other bootable partitions.
Its output will be used to detect bootable binaries on them and create new boot entries.
Adding boot menu entry for UEFI Firmware Settings …
Root filesystem isn’t btrfs
If you think an error has occurred, please file a bug report at “GitHub - Antynea/grub-btrfs: Include btrfs snapshots at boot options. (Grub menu)
Found memtest86+ image: /boot/memtest86+/memtest.bin
/usr/bin/grub-probe: warning: unknown device type nvme0n1.
Found memtest86+ EFI image: /boot/memtest86+/memtest.efi
/usr/bin/grub-probe: warning: unknown device type nvme0n1.

There is no errors in the output you provided - it is as expected