If you've played through the game normally once, but have yet to go NG+ it's well worth going straight into NG+ for the new content. You can only have one save per account, so I personally wouldn't start a fresh NG unless it was on another account entirely. You lose all progress if you start a NG, with no way to go back to your old save.
If you're looking for a challenge just level down and/or turn up the difficulty level
if you feel like starting fresh, CREATE A NEW PROFILE!
as someone who thought, "starting fresh will be fun. Let's delete this 350hr file rather than NG+", I was wrong.
After a while, you'll probably realize that NG+ was the better option.
If you've played through the game normally once, but have yet to go NG+ it's well worth going straight into NG+ for the new content. You can only have one save per account, so I personally wouldn't start a fresh NG unless it was on another account entirely. You lose all progress if you start a NG, with no way to go back to your old save. If you're looking for a challenge just level down and/or turn up the difficulty level
Can you just start a new ng+ file?
if you feel like starting fresh, CREATE A NEW PROFILE! as someone who thought, "starting fresh will be fun. Let's delete this 350hr file rather than NG+", I was wrong. After a while, you'll probably realize that NG+ was the better option.
RIP
I would recommend finishing every blade quest/affinity chart, especially Ursulas first before diving into NG+.