I believe the book is about a protagonist who finds a tape of their deceased parent. Their alive parent works for the same company that killed their parent.
When the protagonist started to look into the company, the company killed the other parent and searched for the protagonist. The protagonist went into hiding whilst also conducting research.
The protagonist tracked down a facility where the company is conducting their secret project. When infiltrating the facility the protagonist discovers the project to be a goal to end world hunger. The company was creating humans that could use photosynthesis to self sustain without additional resources.
The protagonist fell in love with one of the experiments. Whilst gathering intel to whistle-blow the protagonist comes into contact with the creator of the project. A chair-ridden man who’s seeking a new body host to live on but masks his goal with propaganda.
The protagonist flees the grasp of the creator with their intent to not leave their love behind. The protagonist escaped with their lover and unambiguously disappeared whilst releasing the information unanimously.