This is the 28th most frequent Hebrew word.
ביותר
"Most" or "extremely."
Here, "ביותר" functions to signify the highest degree of bravery (אמיץ). It is used to indicate that among people I have known, he stands out as having the most courage.
הוא האיש האמיץ ביותר שהכרתי.
He is the bravest man I have known.
In this context, "ביותר" emphasizes the supreme quality of the adjective "spectacular" (מרהיב). It implies that this view exceeds all others in terms of being impressive.
הנוף הזה הוא המרהיב ביותר שראיתי.
This view is the most spectacular I have seen.
In this sentence, "ביותר" is used to express the superlative degree of the adjective "interesting" (מעניין). It denotes that among the books read, this one is the most interesting.