Investment into renewables, as one example among others.You could make a reasonable argument that the EU should generally refrain from funding infrastructure and other development projects, and that this is a power best reserved for member states.
But don’t sell it short; those programs are generally intended to provide long-term support for the stability of the single market by developing international cooperation and helping the least developed regions and countries catch up. It’s more intertwined with supporting free trade that it may initially seem.
NAFTA on the other hand requires roughly 0 percent, which is markedly better.
NAFTA (or USMCA now) is not really comparable to the European single market even from a free trade perspective. The latter eliminates barriers to the extent that trading with other member states is like trading between different US states. I could load a van up with products, drive them to another EU country, and deliver them to a customer - with no need for customs forms, tariffs, inspections, bureaucracy or anything else of the sort. It’s hard to overstate how much easier this makes trade.
The cost is that removing barriers means greater harmonisation between member states is required on many levels, and the purpose of the EU is to provide the means for that harmonisation.
Again, it’s fine to feel that a better approach is possible. But I think it’s also important to be honest about what the trade offs really are. Neglecting to do that is what led to Brexit.