Popular song lyrics are usually full of double entendres. Because the targeted audience is usually young and matches certain demographics, the lyrics usually have to be explicitly racy and sometimes make plenty of references to sex. This is especially common in rap, pop, R&B. The subject matter is often prurient in taste. Well, as they say, sex sells.
"Break off" is a very good example of this. The phrasal verb "break off" means to make something discontinue or detach. "I am going to break off the discussion." means I am going to quit the discussion. "I just broke off with a partner" means I just parted ways with a partner. So that line could be interpreted to mean something like "I am going to break you off from your old relationship/an unwanted entanglement."
But! "Break someone off" also means, and to certain groups, primarily means "to have sex with someone", especially referring to rough sex. See Urban Dictionary's definitions "break you off" "break me off" which I am disinclined to quote in their entirety in the interest of keeping proper decorum. Just a glimpse: "Usually used as a statement to describe what you are going to do, occasionally used after what you already have done."
That is why it is followed by "let me be your motivation / To stay and give it tonight". "Give it tonight" is another reference to sex. In this context "motivation" is taken to mean something along the lines of "reason". "Let me motivate you to stay with me tonight and 'give it'". That resonates with "'Cause I do it so right". And the lyrics asks the other party to "turn around" and they will give some "innovation" (new ideas). Well, you get the idea. The sexual innuendos are actually quite obvious from the video.
Of course we don't have to interpret the lyrics only that way. Having double meanings is the power of popular music. The song as you say is also a perfectly peppy inspirational song for young girls. We can read those lines as "I will help break you off (from something unwanted). Let me motivate you to stay and fight."
A lot of these songs are written in such a way that they resonate with the target audience. Young girls are expected to like the song well enough to memorize the lyrics and be able to sing the song. So the songwriters always build into their lyrics things that would hook teens because they are cool, like sex, gang life, individuality, dreams and love, etc.
One important thing to note is when you try to critically read lyrics keep in mind that songwriters and singers are artists too, and they share one very important attribute with practitioners in other fields of art: intertextuality. Especially popular musicians. They listen to popular music in the same genre that came before them. So Normani and her songwriters must have had some hit songs in mind when creating this song:
The Roots - Break You Off
Kelly Rowland ft. Lil Wayne - Motivation
Later songs very likely will reference earlier huge hits. And it's not hard to spot similar lines.
In the Kelly Rowland, Lil Wayne song:
Baby I'ma be your motivation
Go, go, go, go, motivation
Go, go, go, go
In The Roots song:
Comin' to break you off