I tried that but with logging enabled (--enable-logging) I see loads of other errors:
[255670:0126/092648.605115:ERROR:command_buffer_proxy_impl.cc(91)] ContextResult::kFatalFailure: AllocateAndMapSharedMemory failed
[255670:0126/092648.605188:ERROR:platform_shared_memory_region_posix.cc(250)] Creating shared memory in /run/user/1000/snap.element-desktop/.org.chromium.Chromium.WBBjqg failed: Operation not permitted (1)
[255670:0126/092648.605225:ERROR:platform_shared_memory_region_posix.cc(253)] Unable to access(W_OK|X_OK) /run/user/1000/snap.element-desktop: Operation not permitted (1)