Greetings community, it has been awhile for me since my last post. But I have been following the on goings on the forum.
ISSUE: Do you have old kernel entries when you boot you machine? Making the EFI boot screen UGLY. Do you want to get rid of them and only have your current kernel entry.
After much research and trying different SUGGESTED approaches to a resolution: editing files, try efibootmgr, etc., nothing solved the ulgy boot screen issue.
Until I had a light bulb moment. This worked for me.
In your terminal launch your File Manager as SUDO. I am using Thunar as my file manager. Use whatever is your preferred file manager.
Navigate to /efi/loader/entries/ folder
Select old/unneeded kernel entry/entries
Delete it or them
Close file manager and reboot machine.
ON re-boot, there should be just One entry, your current kernel.
This solved my issue and I hope you find it helpful in solving your issue as well.