I’m a lefty and fountain pen smearing is an issue. Doubtless there are techniques and inks to optimize for quick drying better than I managed, so I’d encourage you to try and find out for yourself. It depends on how you’re able to position your hand and I’ve only ever managed to write by dragging either all the time or inadvertently when trying to keep my palm raised. It’s a shame because the pens and their output can be quite elegant.