Check out backrest for furniture armchair 3D model on CGTrader for $9. High-quality Polygon mesh mesh by Ostenbakken: 99999 polys, 99999 vertices. UV Mapped.
STL (Stereolithography, filesize: 15.5 MB), OBJ (OBJ, filesize: 15.5 MB), FBX (Autodesk FBX, filesize: 17.1 MB)