By definition it isn’t carbon sequestration if the grams CO2 equivalent (gCO2e) isn’t negative after a full lifecycle study.

I think that should be the definition, but looking at the wikipedia page that you shared, it doesn’t seem to be. At least not by:

• IPCC Sixth Assessment Report: “The process of storing carbon in a carbon pool”
• United States Geological Survey (USGS): Carbon sequestration is the process of capturing and storing atmospheric carbon dioxide

There’s no notion that it has to be have a net negative CO impact, which is exactly what I assume businesses and politicians rely on. They can say “we’re putting away carbon”, which is technically true, but they don’t have to say how much carbon was used in order to do so.

IMO, until at least the carbon cost of sequestration is reported instead of just the monetary cost, the contracts aren’t worth the paper they are written on.