Have you tried a good fountain pen? A good nib makes all the difference.
I've never liked fountain pens because most languages are written left-to-right, which means you will get smudged much more easily than if you were right-handed.
The seemingly best advice I've seen is to learn how to be an "underwriter", aka position your hand north to where you're writing, instead of sideways. I say seemingly because I'm not willing to spend that amount in effort when I can write fine with pens.