Amazing kitbash: HGUC 1/144 AMX−011G−SX Zaku III. Images, info and credits
From the Modeler:
Based on the HGUC 1/144 AMX-011 S Zaku III Mashymre’s Custom, I transplanted the joints of Revive Gundam and modified it to have the proportions I wanted.
Work by boncher_9691 (X account)