Multiple install fails. Grub and boot problems on Lenovo 100S-14IBR

[WytWun]

I have an older Lenovo 100S-14IBR which originally came with a slimmed-down version of Windows.

I have Lite installed & running on a 100S-11IBY which is of somewhat similar vintage to your 100S-14IBR, though I think your system has 64bit UEFI firmware rather than the 32bit UEFI in mine (which was a major roadblock for a while).  If your machine can run the Lite 5.x live system from a USB drive I don't believe there should be any significant reason you can't get Lite installed & running.

A couple of things I noticed from your posted info:
- my machine, and I strongly suspect yours, was GPT partitioned with no legacy MBR support from the factory (I understand this is fairly standard for machines with factory Win10 installs)
- your EFI system partition (sda2) seems to be only 3.7MB - this is far too small for safety (the standard Win10 ESP is 273MB)

In getting my machine converted, I preserved the GPT partitioning and the standard ESP (and a small hidden partition of about 16.8MB that Win10 installs create between the ESP and the primary partition), deleting only the Windows partition and the recovery partition before creating the Linux partitions.

Some of my journey to getting Lite installed on mine is documented in posts in the 5.0rc1 announcement thread (here and here) and the UEFI build test thread (here, where I started with 4.2).  I think the grub issue I encountered with 5.0rc1 was a result of some issues left over from my Linuxium derived 4.2 install; I didn't have any problem installing 5.0 over 5.0rc1 (or subsequently upgrading to 5.2) having rectified the grub problem in 5.0rc1.  However I have had to use Rufus in file-copy mode to put the 5.0rc1 and 5.0 ISOs on a flash drive - no other approach worked.