The capacity isn't the problem. It is the direct write access. If it is USB it tends not to have direct hardware access and it won't work no PC format disk e.g. the ADF Amiga format.

If I use a real floppy disk controller + Linux can write to those disks in the correct format. It works. I am not an expert in how any of this works though. What I have at the moment is sufficient.

I am sure people have had luck with USB drives. I have not.

Amiga disks can't be read by PC floppy controllers whether they're USB or not (barring the 2 drive hack seen here before) because they write a whole track at once and pc floppy controllers can't be programmed to understand their sector headers.

If you want to read/write Amiga disks with a PC you need a greaseweasel or a Kryoflux

Just tried it. It appears I am using cross-dos. I've still never had any luck with USB drives though (just tried a USB floppy I have as well).