This person tends to come alive where someone has to go in first. Start-ups on a blank field, missionary projects, activism for an idea that hasn't even been named yet, new art forms, the kind of negotiation that sits on the seam between politics and belief. I'd say a long, supportive role inside a stable system suits them very badly indeed. Within a year they tend to start suffocating, casting around for meaning and quietly sabotaging the routine, even when on the surface everything is fine.
This Neptune tends to sound strongest in roles where the job is to light people up around an idea. The founder of a movement, the lead of a small team at the very start, the magnetic teacher of a new practice, the artist who hands a generation the words for a feeling it couldn't yet name. Here the pioneering gift works at full stretch without simply going to waste: a team picks up and carries the thing they'd never finish on their own.
Money, with this placement, tends to come in waves, by the project rather than by the salary. A steady wage with a predictable career ladder tends to breed a low-grade gloom inside, even when the sums are large. Freelance work with sizeable fees for a specific vision, grants and producer-style arrangements tend to sit far better.
The main career trap is a string of launches with not one of them carried through to a mature stage. Out of that grows a reputation for being brilliant but unreliable. The remedy is single and dull: take onto the team a person whose strength lies in the finishing and the routine, and pay them properly. Without that kind of partner, almost everything large from this Neptune tends to stall at the level of a beautiful beginning.