I’m no expert, but on a theoretical level: trees—and, more importantly, algae—capture carbon on accident as part of their respiration, which even with risky genetic modification enhancements has a natural limit on volume/biomass-level efficiency.

OTOH, with the right chemical process running at scale (“synthetic carbon capture”, apparently), the sky’s the limit! We might not have the right tech at the moment, but AFAIK there are multiple plausible systems that would work much better than what we have now.