Can't boot to tumbleweed after clean install of openSUSE Leap42.3

As the title says, I can’t boot tumbleweed.
Tumbleweed is detected but when I try to boot it I got this error:

error: file /@/boot/vmlinuz- not found
error: you need to load the kernel first

If need more info just respond to this thread and I will provide.

Thanks in advance.

You have a dual boot ?

I do not even know how to read:nerd:

su - -c 'grub2-mkconfig -o /boot/grub2/grub.cfg'

Please show /boot/grub2/grub.cfg from both Leap and Tumbleweed; upload to and post link here.

As requested, here are the /boot/grub2/grub.cfg:

For Tumbleweed

For openSUSE Leap 42.3
On side note:
I can boot to tumbleweed using the bios UEFI boot but I can only boot in single user mode.
I tried going in to init 3 after booting in single but it won’t. If it is relevant to the problem.

Both of the system is in UEFI and secure boot.
The crazy thing is I recall just now that I used to use two separate /boot/EFI partition for each
but I did a boboo not inspecting the boot partitions when I installed Leap 42.3.

Thank you in advance.

As a follow-up for my previous post
This machine was dual booting Leap42.2 & Tumbleweed
and both are using BtrFs for / and XFS on /home

Now I backed-up my important documents in leap 42.2
then wiped it and made a fresh installation using Ext4
of Leap 42.3 in / & /home.