Lutris needs i386 libGL.so.1 and i386 libvulkan.so.1 to run properly. When you execute lutris it opens initial windows complaining about missing i386 libraries then after closing them it does nothing. Lutris is not masked as multilib and emerges.
~ $ lutris
2020-05-15 11:41:20,841: Running Lutris 0.5.2.1
2020-05-15 11:41:20,842: Using Intel Open Source Technology Center
2020-05-15 11:41:20,842: Running Mesa driver 19.1.7 on Mesa DRI Intel(R) Haswell Mobile (0x416)
2020-05-15 11:41:20,842: GPU: 8086:0416 17AA:220E using i915 drivers
2020-05-15 11:41:20,842: i386 libGL.so.1 missing (needed by opengl)
2020-05-15 11:41:20,842: i386 libvulkan.so.1 missing (needed by vulkan)
INTEL-MESA: warning: Haswell Vulkan support is incomplete
2020-05-15 11:41:26,833: Vulkan is supported
2020-05-15 11:41:30,220: Updating DXVK versions
Traceback (most recent call last):
File "/usr/lib/python3.7/site-packages/lutris/gui/application.py", line 173, in do_activate
self.window = LutrisWindow(application=self)
File "/usr/lib/python3.7/site-packages/lutris/gui/lutriswindow.py", line 100, in _init_
self.game_store = self.get_store()
File "/usr/lib/python3.7/site-packages/lutris/gui/lutriswindow.py", line 293, in get_store
self.show_installed_first,
File "/usr/lib/python3.7/site-packages/lutris/gui/views/store.py", line 117, in _init_
self.modelsort = Gtk.TreeModelSort.sort_new_with_model(self.modelfilter)
AttributeError: type object 'TreeModelSort' has no attribute 'sort_new_with_model'