In terms of scenic spots, it is recommended to go to OCT Grand Canyon or Chaxi Valley. Both of them are paid attractions, and I personally recommend the Grand Canyon.
If the park is free, I recommend Shenzhen Talent Park. You can see the panoramic view of Houhai CBD. In addition, it is connected with the mangrove bay leisure belt. You can take a walk in mangrove bay. The location is very good.
I have their travel notes, so I can have a look.