For what it's worth, I successfully downloaded that windows iso from microsoft less than a week ago from a windows machine, and used it to reformat that same machine without any issues or workarounds.
They offer to download Media Creation Tool, which itself either downloads the ISO, burns DVD or makes an USB with installer for you.
There is one subtle difference between the ISO you can download and what the tool downloads: the ISO contains install.wim file, which is larger than 4 GB (i.e. it won't fit on FAT32 usb, if you are going to make it yourself; it is fine with UDF, when burning), while the MCT image contains install.esd, which uses different compression and fits into FAT32.
TLDR: if you want USB stick with installer, use the Media Creation Tool. You won't be able to make it easily from the ISO (aside from wim-splitting, esd-recompressing, or using NTFS if your UEFI supports it).
That also explains why I always had to flash the ISO to a USB stick with Rufus (inside VirtualBox) - just `dd` or `cat`ing it onto /dev/sdX never worked.
The magic boot sector that all those tools like Rufus create, is needed only for legacy boot.
The Windows 10 ISO from the download is using UDF filesystem and is intended for burning. If you dd it to a block device, very few firmwares support that from non-optical drive. Prior to 1809 release, it's install.wim was smaller than 4G, so you could make UEFI installer by just copying all the files to USB drive, but since 1809, the easier way is just to use the Media Creation Tool. The harder way is to recompress install.wim into install.esd, or just use NTFS if your firmware has the support (e.g. Intel NUCs do).