If you have a hard time contributing to starting on projects or resolving problems, AND you have a hard time contributing to finishing projects or resolving problems, you’re a junior X (where x is programmer, engineer, sysadmin, etc).
If you can contribute to starting on a project/problem but have a hard time finishing it, OR you have a hard time starting on a project/problem but can contribute to finishing it, you’re an X.
If you can contribute to starting on a project/problem, AND you can contribute to finishing a project/problem, you’re a Senior X.
Not sure the current term of art to being able to start and finish projects / solve problems and your work regularly being good and reliable, maybe Architect or something like that.