Just use

MESA_LOADER_DRIVER_OVERRIDE=zink program

MESA_LOADER_DRIVER_OVERRIDE=zink glmark2

returns:

=======================================================
    glmark2 2021.02
=======================================================
    OpenGL Information
    GL_VENDOR:     Mesa
    GL_RENDERER:   zink Vulkan 1.3(Radeon RX 7900 XTX (AMD_OPEN_SOURCE))
    GL_VERSION:    4.6 (Compatibility Profile) Mesa 23.1.3 - kisak-mesa PPA
=======================================================
[build] use-vbo=false: FPS: 4556 FrameTime: 0.219 ms
[build] use-vbo=true: FPS: 5125 FrameTime: 0.195 ms
[texture] texture-filter=nearest: FPS: 4598 FrameTime: 0.217 ms
[texture] texture-filter=linear: FPS: 4522 FrameTime: 0.221 ms
[texture] texture-filter=mipmap: FPS: 3700 FrameTime: 0.270 ms
[shading] shading=gouraud: FPS: 3308 FrameTime: 0.302 ms
[shading] shading=blinn-phong-inf: FPS: 3900 FrameTime: 0.256 ms
[shading] shading=phong: FPS: 4038 FrameTime: 0.248 ms
[shading] shading=cel: FPS: 3874 FrameTime: 0.258 ms
[bump] bump-render=high-poly: FPS: 4156 FrameTime: 0.241 ms
[bump] bump-render=normals: FPS: 4080 FrameTime: 0.245 ms
[bump] bump-render=height: FPS: 3540 FrameTime: 0.282 ms
[effect2d] kernel=0,1,0;1,-4,1;0,1,0;: FPS: 3888 FrameTime: 0.257 ms
[effect2d] kernel=1,1,1,1,1;1,1,1,1,1;1,1,1,1,1;: FPS: 3569 FrameTime: 0.280 ms
[pulsar] light=false:quads=5:texture=false: FPS: 3386 FrameTime: 0.295 ms
[desktop] blur-radius=5:effect=blur:passes=1:separable=true:windows=4: FPS: 3010 FrameTime: 0.332 ms
[desktop] effect=shadow:windows=4: FPS: 3064 FrameTime: 0.326 ms
[buffer] columns=200:interleave=false:update-dispersion=0.9:update-fraction=0.5:update-method=map: FPS: 1199 FrameTime: 0.834 ms
[buffer] columns=200:interleave=false:update-dispersion=0.9:update-fraction=0.5:update-method=subdata: FPS: 1613 FrameTime: 0.620 ms
[buffer] columns=200:interleave=true:update-dispersion=0.9:update-fraction=0.5:update-method=map: FPS: 1811 FrameTime: 0.552 ms
[ideas] speed=duration: FPS: 2351 FrameTime: 0.425 ms
[jellyfish] <default>: FPS: 3041 FrameTime: 0.329 ms
[terrain] <default>: FPS: 1259 FrameTime: 0.794 ms
[shadow] <default>: FPS: 3015 FrameTime: 0.332 ms
[refract] <default>: FPS: 3112 FrameTime: 0.321 ms
[conditionals] fragment-steps=0:vertex-steps=0: FPS: 4143 FrameTime: 0.241 ms
[conditionals] fragment-steps=5:vertex-steps=0: FPS: 4074 FrameTime: 0.245 ms
[conditionals] fragment-steps=0:vertex-steps=5: FPS: 5349 FrameTime: 0.187 ms
[function] fragment-complexity=low:fragment-steps=5: FPS: 5058 FrameTime: 0.198 ms
[function] fragment-complexity=medium:fragment-steps=5: FPS: 4110 FrameTime: 0.243 ms
[loop] fragment-loop=false:fragment-steps=5:vertex-steps=5: FPS: 4512 FrameTime: 0.222 ms
[loop] fragment-steps=5:fragment-uniform=false:vertex-steps=5: FPS: 3646 FrameTime: 0.274 ms
[loop] fragment-steps=5:fragment-uniform=true:vertex-steps=5: FPS: 3241 FrameTime: 0.309 ms
=======================================================
                                  glmark2 Score: 3571 
=======================================================

https://docs.mesa3d.org/envvars.html?highlight=mesa_loader_driver_override#envvar-MESA_LOADER_DRIVER_OVERRIDE