So you get demonetized after hit by "Reused Content" then don't worry, you can still repair it if your video is original one. I have a channel that get strike and "reused content". And finally can be back to remonetize again. You can follow my guidelines bellow.
First thing First make sure your content is All original, if you reupload someone video this will not help you. If you have video that have copyrighted music, then delete it.
1. Check Your Video Title
You can get reused content just by title, although your video is original, so make sure you change your title, and do not make same title for video. But if so you can add part 1, part 2, part 3, session 1, session 2, etc.
2. Make a new video with commentary / cam.
Commentary / cam will add unique of your video. It will add more value.
3. If you don't want add commentary / cam then write deailed description in your video. (Your video must original).
This also help to get chance in review, make sure you write enough good detailed in description and show what are you doing in video, your tools, your rig, everything maximize in description. But do not keywod stuffing (add huge keyword in description).
That's it after your check the video and if it's good condition (no copyright claim, all clean). Then you can reapply, don't forget to pray in your belief... :)
Have a nice day.. :)