Short answer: no, there are no proper GPU drivers.
1. With latest Armbian Desktop image from Download section it's XFCE, Xorg and modesetting driver with Glamor accel enabled (by default) on softpipe making it extremely siow.
To disable Glamor:
/etc/X11/xorg.conf.d/00-no-glamor.conf
Section "Device"
Identifier "gpu"
Driver "modesetting"
Option "AccelMethod" "none"
EndSection
2. With the official Debian image from StarFive it's GNOME, Wayland and proprietary PowerVR driver.
Driver: pvr (Imagination Technologies PVR DRM) version 1.19.6345021 (20170530) -- GPU
Driver: starfive (VeriSilicon DRM driver) version 1.0.0 (20191101) -- CRTC and Encoders
There is some Vulkan 1.0 but it's not working,
no OpenGL, and
flaky OpenGL ES.
Imagination Technologies produced Mesa driver via powervr-next initiative for 3 Rogue GPUs, but not the model used in JH7110 (BXE-4-32).
I guess StarFive are doing their best with what they have been handed over -- an unmaintained binary driver from ImgTec. If history is of any indication, then similar approach went nowhere with Creator CI20 MIPS SBC, from the ImgTec themselves in 2015.
https://forum.rvspace.org/t/visionfive-2-debian-202405-released/4329/57
https://forum.rvspace.org/t/opensuse-tumbleweed-with-ati-radeon-r9-290-mainline-kernel/4545