I hear your frustrations and upset. You are all alone with this project, and without support from your boss. He sounds very hands off and clueless about the amount of work you've put into it, and about how much positive progress you've made. I can understand feeling deflated after he wanted to switch to Python. Please be proud of your own progress despite your boss's lack of acknowledgement, though. You don't need his affirmations to know you've done a great job all on your own figuring out this huge project. On the bright side, at least he listened to your guidance about the reimplementation in Python. That means he must trust your judgement. He is just clueless, and you're left to figure it out yourself.

i also understand your frustrations about your coworkers and the management of your group. You sound like you are very dedicated and hard working. It's so hard to be the one person in a group working hard and to not only have that go unnoticed and unacknowledged, but then to have the slackers excused for not working.

In my last job, it was very similar to yours. I was the hardest working on my whole team and everyone else goofed off all day long, including my boss. No one above cared how hard I worked or if I was the one shining star in the department pulling in the most success with our clients. I still got let go because my boss was threatened by my skills, and because the upper management rewarded and retained the slackers and liars vs the ethical, honest and hard working employees.

It's unfair and not right. I feel your pain. Hang in there, and hold onto any positives you can find. You are doing a great job learning and figuring out this project all by yourself.