In a typical "one man army" situation or "teams" with only 2-3 members, there are totally unnecessary to create these roles. There are just designers who have to design, without any other titles. With 2 designers the UX maturity level is so low at a company, that a PM, who also oversees the developers, is usually enough to manage the designers as well.
I was senior UX designer, lead UX designer, UX manager and also principal UX designer in the last 5 years and in my opinion, leadership roles start at a team size of 4-5 designers. A UX manager or principal UX designer is needed when the team already has 4-5 designers, and they are working on different tasks, with different dev teams, stakeholders, etc., so someone has to "manage" their time, help them with stakeholders and solve their problems, reduce bottlenecks, so they can work without any disruption. Otherwise, a senior designer should be enough to manage these things. When there is only one product, and a handful of key stakeholders, putting someone between the designer and the stakeholders is contra productive.
In your case, I think the UX manager is just a careerist and definitely wants a leadership role and not because it is good for the company. There is no point in such a team and at such UX maturity level for such roles.