For a short period I looked into carbon stuff and while forests were good, wetlands were deemed much bigger sinks.

It feels like wetlands is a huge ignored area. If what I read at the time holds (I think it was like 6-12x sequestration rate in some regions), a simple thing like rising sea levels would have a huge impact.

And anthropogenic destruction of wetlands is also a huge issue and one that is relatively easy to reverse in a lot cases (dams, rerouted rivers). And in some cases, water can just be rerouted occasionally to create temperarly wetlands that are good ecosystems as well. Mossy Earth I think is doing some of these.