You correctly point out the problems of the vague goals XR has, and the nonsense of their/Chenowith's 3.5% figure. But you miss that the problem is not merely AGW but actually technology itself. If humanity remains disconnected from Nature and in service to technology (advancing toward its own autonomy) we will continue to suffer all the other ills beyond heating the planet: mental and physical problems for many people, biodiversity loss and deforestation, and further concentration of power imposed down upon us, diminishing real freedom. And when it comes to solving the pervasive problem of technology, there can be no adequate reforms.
jorgecluni.medium.com

"The industrial revolution and its consequences have been a disaster for the human race." (I.S.A.I.F., 1995)