I don't know whether this answer can satisfy you.
This is troubling me because the purpose of my life is to keep on
learning and improving myself.
You didn't mention what is meant by the term-- 'improving myself'. Different people have different aims according to their philosophy. But those who could understand the potentialities of human have clearly mentioned about it. The inquiry of human will not stop until he realizes himself clearly. Then only one can understand clearly what that term means.
If one could realize himself he would explain that term in a different way. I don't wish to mention it...please 'listen' to Vivekananda.
Swami Vivekanada says:
The ultimate goal of all mankind, the aim and end of all religions, is but one—re-union with God, or, what amounts to the same, with the divinity which is every man's true nature. But while the aim is one, the method of attaining may vary with the different temperaments of men.
I mean what if one day, we know everything and did everything to
improve ourselves and there is no more room for improvement?
If there is a term--'Vedanta' (the limit of knowledge) and many great men have used it, your doubt is true.
You can verify whether the term 'Paramahamsa' refers to any kind of improvement.