I've never used DOS/W98 to create such disks. Although I can boot W98SE in my tweener, having also an XP results in a killer combo when paired with SamDisk.
If you're stuck in DOS, you can use the aforementioned DITT; but beware that while it excels writing 5.25" floppies into old 360KB drives, when working with modern 3.5" ones it could fail miserably. These 3.5" drives are HDD, while the originals are DDD and that means you need to write the D77 image (dumped with a double density drive) with double-step enabled and that's why you need a tool capable of doing that.
I mean, IIRC DITT doesn't have such feature so you can, I'm wildly guessing now, use SamdDisk in any other PC to transform D77 images to IMD (
ImageDisk) ones and then, using IMD, a pure DOS tool capable of write images with double-step, to write the converted images to floppies.
Btw, welcome to the forum!. Maybe you can present yourself
here and tell us about your fave machines and if you have an original keyboard for a FM-77AV40SX