I recently started working for a small team. At the same time company hired another person for the same position. We were meant to form two person team, because our competences are complementary. That's what our manager told us.
A couple of weeks later it was clear to me that my coworker's skills are not fit for the role at all. Every task needs to be revisited by me (that's what my manager requested considering my education) and all errors needs to be corrected. Quality of my coworker's work is bad to the point I prefer to do it on my own instead of correcting mistakes. Right now they are doing only small tasks that take way longer than they should. Situation wouldn't be bad, but we are treated as a team and all successes and mistakes are assigned to us as a whole (by the team and manager), not individually, where it would be clear I am overburdened. On top of that, there are a lot of small details in their behavior such as: "stealing" internal communication in a way that it looks like they are committed and hardworking. Their behavior made some of the co-workers to be mean to me - they are thinking we are friends and we are not.
I tried to enforce some task assignment, so both of us would be fully accountable for a part of the job, but manager said they are interested only in effects, not who did it. I tried explicitly stating that I did the whole task, but it's overlooked every time. I can clearly see that the problem is more complex than my coworker's behavior, but their actions exposed what's wrong with the company. Manager themselves stated that team spirit was better before we joined.
I am planning to change industry in a couple of months for other reasons, but I would like to work where I am with a respect to the job I am doing. How can I deal with such situation where I can't really count on my manager, first person I would go when I can't resolve problem on my own? I like the tasks I am assigned, but I would like to be appreciated for them. Also I don't like that someone's behavior is worsening my relations with others.