しゅうし終始shuushi
1.

The quality of maintaining a consistent state or attitude from the beginning to the end of a situation, without any changes throughout.

2.

A condition in which a person or entity holds onto their original stance or behavior throughout the entire duration of an event or discussion, exhibiting unwavering commitment.

3.

A continuous manner of behavior or approach that remains unchanged and steadfast from the start to the conclusion of an occurrence.

Example:

前の会社では何でも屋に終始したので今度は専門職に就きたい。