Don't pay the cost like I did. Large ISOs (>4 GB) + wrong settings = an unreadable USB or a wasted stick.
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UEFI system + 5.9 GB Ubuntu ISO
$\Rightarrow$ Do NOT use default setup (FAT32, even though Rufus ISO includes many files each less than 4GB, I don't know why but it can break, probably regarding wrong logic, anyway, you shouldn't just throw it in with the default values without even reading it, just because you’re busy.). - Use Rufus
$\to$ DD Image mode (safest). Windows may not "see" the USB afterward-that's normal for boot media.