If it were a BF shooting her she would be more talkative to him. Probably less professional and not faking it.
The shooting is fine, not every BF has a shit camera or doesn't know how to use it. And a site of this content has to have so many interpretations as it would be shot by many not a few.
But there would be more going on between the guy and girl.
Not this script but something like this to start.
Opening shot 1
Opening shot 2
Opening shot 3
Opening shot 4
Each girl must do it her way, some nervous a bit and some clearly not. It was shot for a different market and needs to be altered a bit but it gives you some ideas.
Then closing maybe something like this.
Closing shot
Again needs changing to suit the actual niche, the girls talks to her boyfriend about the fun she has doing the video for him. But the way she climaxes would be the way a GF climaxes in front of her lover if they were shooting a video. Don't ask how I know that.
Sorry don't have specific samples of how to do it and it's obvious these are for a different market, just to give you a few thought. The script needs changing but the basic idea is she's doing for her lover as a prelude to a fuck and teasing the crap out of him. Each girl will react differently to the camera, bring that out.
The camera might be shaking while he strokes his penis and the girl teases him to. Don't ask me how you achieve that one.
Most Ex GF content shot professionally IMO looks like 2 strangers in the same room.