i gather these monetary goals are more important than your other goals. in the world we live in, there’s nothing wrong with that, and there’s nothing to say that making a lot of money outside of something directly related to working in conservation is incompatible with advancing conservation overall.
just find your way to help the cause in whatever way you can regardless of whatever career you ultimately choose, and, importantly, help to inspire as many others as possible to love science and conservation.
I can’t speak to the current job market (I’m in the US) for those with environmental or biology degrees; it’s taken a turn (hopefully temporarily) for the worse. I’m recently retired after 30+ years working for state and federal agencies as a wildlife biologist and also in environmental compliance work (the latter involving complying with environmental laws and regs for various agency projects). I’m glad I took the route I did as it mostly aligned with my interests. Pay was not great compared to other careers I could’ve pursued with a MSci degree but there are many such jobs that would’ve felt like a death sentence if I had to take them.
I’ve been holding back from participating because I didn’t feel that my environmental job experience was much to speak of. As to promotion opportunities: I would have been thrilled to be promoted from seasonal to permanent. When waiting for that to happen became unsustainable, I moved on to other fields, and am not currently working in an environmental job. It took me a while to move past resentment about that.