To install a new kernel we can use the command below to list the available kernels.

┬─[tiago@desktop:~]─[09:03:40]
╰─>$ sudo mhwd-kernel -l
available kernels:
   * linux419
   * linux510
   * linux515
   * linux54
   * linux61
   * linux62
   * linux63
   * linux64
   * linux62-rt
   * linux63-rt

And to install a new kernel.

┬─[tiago@desktop:~]─[09:03:43]
╰─>$ sudo mhwd-kernel -i linux61

To update efi, mount the ESP partition.

┬─[tiago@desktop:~]─[12:29:52]
╰─>$ sudo mount /dev/nvme0n1p2 /boot/efi

And, update the grub boot menu.

┬─[tiago@desktop:~]─[12:29:52]
╰─>$ sudo grub-mkconfig -o /boot/grub/grub.cfg
┬─[tiago@desktop:~]─[12:34:26]
╰─>$ sudo grub-mkconfig -o /boot/efi/grub/grub.cfg

Reboot and check the running kernel with the below command.

┬─[tiago@desktop:~]─[12:29:52]
╰─>$ sudo mhwd-kernel -li
Currently running: 6.1.31-2-MANJARO (linux61)
The following kernels are installed in your system:
   * linux515
   * linux60
   * linux61
   * linux62