As I understand from using LEAP and other energy modeling tools, we often take a broader perspective, looking at the energy system on a national or country level rather than just as an individual plant or investment plan from the viewpoint of a renewable energy developer. In this context, the costs—whether covered by developers or through public subsidies—are considered collectively.
If your goal is to analyze the gap between developer capability and the actual costs, and you're assuming that this gap will be covered by government subsidies, this type of analysis might need to be conducted outside of LEAP.
It sounds like you might be more interested in incentives rather than subsidies. Typically, subsidies are directed towards vulnerable or low-income groups. If you're looking to analyze how much subsidy is needed to cover the cost burden for vulnerable or low-income consumers, you might want to explore LEAP's new feature, 'Affordability Analysis.' However, this would require your model to accommodate disaggregation between different income groups.