This is almost certainly a hardware issue rather than a driver problem. Linux includes support for Intel graphics (Intel have been very good at providing and updating source code for linux to support their graphics). But your particular version of the Intel Graphics is probably too old to provide the openGL features that Unity needs. Intel's support for openGL 3.2+ started in 2012 with their HD 4000 GPU.
8086:0046 is Intel HD graphics from 2010. From some quick googling, I think it doesn't even support OpenGL version 2, while Unity requires OpenGL 3.2 to 4.5 on Linux.
To verify this, try running
glxinfo | grep -i opengl.version to find out what version of openGL your Intel HD GPU supports. e.g. on my system (with an ancient Nvidia GTX-560 Ti), it returns:
$ glxinfo | grep -i opengl.version
OpenGL version string: 4.5.0 NVIDIA 384.111
That means it is OpenGL version 4.5.0, and the driver is the proprietary nvidia driver version 384.111.
If you get a number less than 3.2 for the openGL version, then Unity will not work on your GPU.
If this is on a desktop machine with spare PCI-e slots you could install an AMD or Nvidia GPU (even the cheapest current models will be many times faster than ancient Intel HD graphics, faster than ANY Intel graphics. Intel GPUs are not noted for their speed - they're adequate for basic 2d graphics like a desktop, even some lightweight 3d graphics, and not much more).
If this is on a laptop, there's nothing you can do. They're not very upgradable.