What's the solid product of the reaction of liquid ammonia with excess sulfur?
I don't think this question has a simple answer.

This paper's first page (all I can see without a subscription) indicates that sulfur can dissolve in liquid ammonia, producing hydrogen sulfide (as the question correctly states) and... complicated stuff: S7N-, which disproportionates into S4N- and "an" ammonium polysulfide (maybe (NH4)2S6, maybe another composition).

The paper's first page also refers to the system's light sensitivity, so if you don't keep it in the dark, you may get different products.