Multi-boot USB that doesnt require CSM on or Secure-boot off?

Well, I used Both methods...
The first method via editing the BCD to point to different Folders on USB
The second method via custom Recovery Media...

For Me??? Custom Recovery Media...
You'll have to decide your preference....
Yes, like everything - the media would need to be updated at sometime along the way..
Test the Recovery Option w/Boot.wim - it will more or less make the other 3 options obsolete

okie doke. hit my threshold. i have a slew of data here and unsure what needs to go where.

i have a fully mounted windows 1909 image. i have an install.wim on my desktop. a winre.wim. my bootable macrium and minitool (and memtest)

boot and efi folders are easy enough.
bootmgr and bootmgr efi as well.

a little perplexed on the rest. you say sources is for windows 10 install media, yet my sources folder (which would be great to have on there) unfortunately is too big due to the size of install.wim and the fat32 limitation.

as for the third party stuff, easy to understand to rename their respective "sources" folders to a recognizable name and drag those over, but you go on to say "All Other Root Files/Folders From Source Media To this USB" so does that mean my usb will not look like your image there?

cause quite a bit of other "stuff" exists on the recovery disks that isnt present. Avoiding the boot and efi folders, again easily understandable.

finally the recovery folder, where is that guy coming from? I dont have "recovery" media if your referring to the windows recovery environment as I had a partition mishap and lost my recovery partition until the next windows update. This is part of my motivation to get something made up for myself as quick as i can just in case.

needless to say, windows is giving me an error when i attempt to build a recovery drive (to presumably get those files) likely due to the aforementioned.

OK we will do this a different way....
Create your USB by copying all the contents of Windows Setup media ISO to the USB
Copy MY boot files to USB overwriting existing Windows Setup Media Files...
Download and Copy MY Boot.wim into "Recovery" Folder
Mount your MiniTool Media ISO and copy the Boot.wim from ISO/Sources to USB/Minitool
Do Not worry about Macrium yet.............. Test Boot your New Media USB

Copy the Renamed "Sources" folder & All Other Root Files/Folders From Source Media To this USB

If File or Folder exists in ISO - but not USB - then copy it from ISO to USB

As Macrium usually has a Drivers Folder and a few extra Files in ISO - that will need to be copied to USB

I hope that make my statement more clear...
As sometimes my experience gets in the way of a very simple explanation