Rather than trying to spend money offsetting your carbon footprint you would be better off spending your money reducing the cost of new technologies so that carbon is not profitable to burn.
The best suggestion I have heard is slash and char of the tropical rainforests. The idea here is that instead of the current slash and burn agriculture is you instead pay the locals to produce biochar and bury the resulting char back in the soil. You can fix around 30t/C per hectare from the regrow and by turning the forest into biochar you prevent the carbon being released again into the atmosphere. There is just enough rainforest to balance the carbon being emitted, although it will soon be overwhelmed by the growth of emissions.
An entity that can remove carbon from the atmosphere will be able to sell it there. So the initial focus will be on agricultural practices because that’s where it can most easily be done.