The only way your going to get scratches from sanding out is more sanding.
Get yourself some wet dry paper, a bit of water, oil, or windex
And settle in.
I would wrap the handle and pommel in Saran Wrap and painters tape to avoid putting marks on that. Then start at an appropriately coarse grit to remove the existing scratches, then go up, ie from 120 to 180 etc. spend plenty of time at the middle grits, and I would recommend a backer, and using only pull strokes from tang to tip. Watch a few YouTube vids.
Alternatively: you could try scotchbrite to blend them - might work ok but sorta a bandaid.
Or best of yet: find someone with a proper belt sander that has the requisite finishing belts: like trizact, scotchbrite, or cork depending on how far you want to go. What will take a few hours by hand will take a few minutes in the grinder to a skilled operator.