You should be able to batch CPU-side drawcalls by packing multiple meshes into bigger vertex buffer, then generating draw parameters for every object into SSBO/UBO, and then utilizing ARB_multi_draw_indirect to draw everything at once. To change textures inside these batched drawcalls you might need ARB_bindless_texture. This talk is helpful: https://www.gdcvault.com/play/1020791/Approaching-Zero-Drive...

I don't know if these extensions are available on Pi driver, though.