I got the same error "could not initialize canvas" while running glmark2-es2-wayland.
It also crashes if I switch the login manager to gdm3 (after logout or reboot). Running:
/usr/bin/gnome-session --session=gnome --debug
and gnome-session showed error info about could not enable the hardware acceleration for Wayland then crashs.
Yes, I still using Chromium, Vivaldi, and Firefox.
About Xfce and LXDE, I don't know why I feel like LXDE is ~1.5 faster/smoother than Xfce.
It just my experience, anyway!
I have used Armbian Debian Stretch Desktop 4.19.y for 3 days.
And I see that LXDE / vivaldi give better user desktop experiences than Armbian's default Xfce / Chrominum.