Pop!_OS : setting kernel parameters (boot loader options) permanently is not working

Was experimenting GPU passthrough with QEMU (following the steps given here) on Pop!_OS and in the process I added kernel parameters.
Now I want to remove the intel_iommu=on kvm.ignore_msrs=1 vfio-pci.ids=8086:3e9b to regain locked VGA card. However altering parameters with popos seems not working for me. I am not an advanced user so I am sure I might be missing something here.

I tried (1) kernelstub, (2) updating grub and (3) modifying loader.conf (4) changing configuration (as explained here), but no luck. You can find in the screenshot that, kernelstub is reporting only quiet splash being the active kernel parameters, however cmdline shows (otherwise) currently effective options.

Wondering how to alter the kernel parameters permanently so that VGA card to be returned to the host system. I had similar problem with Ubuntu, changing /etc/default/grub file and updating it easily solved it.

Answer

Attribution
Source : Link , Question Author : Pavan G R , Answer Author : Community