Now I'm not sure about making those 1 thing or relating them at all.

Max Ajl is famously at least hopeful about Degrowth but rails against half-earth socialism.

Degrowth has nothing to do with population, it claims that overconsumption for the purpose of profit (like single-use, non-repairable, non-renewable) all correlate much more strongly to destruction that population. Degrowthers often see humans living harmoniously with nature as the goal, and often in integrated ways.

Half earth socialism sees earth being split into 2 portions and "not touching" some and allowing others to have human activity. It misunderstands the issue at base and assigns a solution which will almost definitely require genocide of those who already live harmoniously with the environment in places that humans are forced out of.