Your approach is sound. You won't find a 0.015 mm nozzle, but maybe a 0.15 mm nozzle, but it's still an FFF process. Resin will get you a decent resolution and maybe a bit of brittleness. SLS is going to be much stronger and more durable.

Negative space (debossed text) with a resin fill is probably the right direction. If you mix the resin properly, it will cure without complications. I have UV curing glue that might be able to be tinted then cured with a UV light. It's astonishingly strong and durable.

If the cap has a flat top and the debossed text is printed to match, each letter or shape could be inlaid with adhesive. It's likely to be tiny and difficult to manage, of course.