sudo apt install gnome-disk-utility
then select "Partitioning: No partitioning".
First, select "Format Disk" from the top right corner (NOT "Format partition" ),
And only then select Additional partitioning options - "Format partition" , FAT, Next, Format.
"Disks" (gnome-disk-utility) can also write an iso to the usb: after having formatted the usb as said above: go to Additional partitioning options as before, and select "Restore partition image", then select the Linux iso.