GTK4+nvidia-340: No provider of glGenSamplers found
When I try to open recent devel versions of Epiphany (flatpak's from gnome-nightly) I get the error about glGenSamplers. I confirmed the same thing happens with devel versions of gnome Calculator, and suspect it's all new GTK4 apps. It suggests a problem with OpenGL 3.3, which the nvidia-340 proprietary driver I'm using does indeed support, and glxinfo confirms.
~$ flatpak run org.gnome.Epiphany.Devel
(epiphany:2): epiphany-WARNING **: 14:24:35.018: Failed to search secrets in password schema: org.freedesktop.DBus.Error.ServiceUnknown
No provider of glGenSamplers found. Requires one of:
Desktop OpenGL 3.3
GL_ARB_sampler_objects
OpenGL ES 3.0
~$ flatpak run org.gnome.Calculator.Devel
No provider of glGenSamplers found. Requires one of:
Desktop OpenGL 3.3
GL_ARB_sampler_objects
OpenGL ES 3.0
~$