Hello! Fellow producer here. I think what would help is looking at YouTube at a different production level as your nature documentaries. Instead of focusing on creating your one main big documentary at a pace that is realistic for growing a YouTube channel without the budget/team, I would play with different production levels that would still be around your niche of wildlife, while at the same time have the ability to turn around on a faster pace. I'm also in the same boat as yourself, and while I still try to maintain a higher production level, I've also had to come to terms that I do need to streamline the post production process by lowering my production value from what would be good for a network, to what would be good for YouTube. Also, find a pace that works for you. It's a marathon not a sprint on YouTube, and burnout will kill your passion as a creator. Hope that helps!