You might start with the fact that fossil fuels get nothing like $5.3 trillion in subsidies. That's almost 7% of world GDP.
Direct (pre-tax) subsidies are around $480 billion, and most of that is petrostates selling gas to their citizens at below market prices. Developed countries supply rounding error level direct subsidies to fossil fuels and most of those are generic business development tax breaks provided to any large corporation.
You get those ridiculous multi-trillion numbers that places like the IMF and Grist put out by pricing externalities - e.g., counting as a "subsidy" any side-effect of the use of fossil fuels. But those externalities are notoriously broad - for instance, IMF counts road construction and maintenance as a fossil fuel subsidy. So this solar road would get that "subsidy" plus whatever the extra cost of the solar road was. IMF also counts road accidents as a fossil fuel subsidy - which would now become a solar subsidy.
The closest IMF gets to pricing externalities that are specific to fossil fuels is climate change, but those are based on mostly on projections and not current conditions. If you want to count not banning something as a "subsidy", feel free, but it's not a common point of view.