Recommendations for finely detailed replica. Suggestions? (Destiny 2)

Hiya folks,

I'm looking to make a replica from Destiny 2, called "Malfeasance".
The issue here is the very ornate and finely detailed sides of the weapon.

The plan will probably be to 3D print the weapon and add the side detail afterwards to reduce some sanding. As for the detail, i was hoping some of you would have some suggestions on how to tackle this challenge.

Thanks for listening, and I look forward to your responses!

The detail doesn't look raised but rather painted on. Maybe a calligraphy pen? As for the gun itself, its on Thingiverse.