Video editing with text to speech
You can do this, but why bother.  It is far faster and easier to record your dialog in multiple takes.  As long as you can naturally speak a sentence or two at a time, you can narrate your own video by carefully editing your dialog from multiple takes.  DAW tools will even play the video for you while you are dubbing over it and let you hear what happened before and after your take in order to give you context.  This is faster and will sound better than your text to speech solution.

If you still really want to do text to speech, I would recommend taking the same kind of approach.  Make clips for each of the phrases you need and then move them in to the video and place them as needed.