What should I do about a developer who doesn't seem able to develop?

For context I've been in my first junior developer role for about 16 months now working on backend business logic features

We have another junior developer who has been on the team 9 months and they are still fundamentally incapable of working independently on anything, even with support they don't actually solve anything themselves

This last month alone I've peer reviewed 4 of their pull requests and fundamentally everything is wrong with what they do. It peaked most recently with about 60 change requests for a ticket that was a fairly trivial field name change. They are never correct to the specification document we are given, they often won't successfully build, and on rare occasion when they prepare tests they are either wrong or incomplete

Their work reeks of the fact they basically look for something similar in the code base, copy and paste it with a few changes to make it look similar to the spec it's for, even doing that it's full of mistakes and if there is even anything slightly tricky or new to implement then they will still submit the pull request of their work without any attempt to actually solve the problem

My issue is I'm aiming to level up soon which means demonstrating mentoring skills, and this is something I'm perfectly happy with when the other dev can actually problem solve and think about an issue but need guidance from someone more knowledgeable of the domain and code base. But the developer I'm talking about here can basically do two things. Copy and paste with field name changes, or hold their hands up and say "how do I do that?". Asking them what they've tried already results in a dumb founded expression like "huh? I'm supposed to try and solve something?"

I've been perfectly fine supporting and onboarding even mid and senior level developers to the team, but how do I protect myself that this devs lack of ability isn't a reflection of my attempts to mentor them without basically just telling tales that they aren't competent enough to be a developer?