Hello, I hope you are doing well

It doesn't matter if you leave the practical exam or theory exam, because if you appear for 1 and leave the other you will be considered fail in that subject.

It is necessary for you to pass both the practical and theory exams to pass in a particular subject.

Also, you don't have to wait for next year's Improvement exams, you can appear for compartment exam this year only and get your result. After that whether you are satisfied with your score or not depends on you, if you want to improve your score then you can appear for improvement Exams next year.

Hope this helps.