First of all make sure that both the Extension Pack (host) and the Guest Additions (guest) are installed.
The Extension Pack provide additional support for virtual USB 2.0 (EHCI), virtual USB 3.0 (xHCI), VirtualBox Remote Desktop Protocol (VRDP), host webcam passthrough, Intel PXE boot ROM, and other experimental features. It needs a payed license for corporate usage. If the aforementioned features aren't required then you can go without. However, among the experimental and often undocumented features, we find something that improves overall performance both in 2D and 3D. Whether or not it impacts this specific user scenario remains to be tested.
The Guest Additions install specific drivers or, in case of Linux guests, more correctly "kernel modules" for better support of the virtualized hardware. In Ubuntu guests or derivatives it can be installed directly from the official repositories.
Then understand the different graphics controller options available: https://superuser.com/questions/1403123/what-are-differences-between-vboxvga-vmsvga-and-vboxsvga-in-virtualbox
Test which one provides the best performance and understand that even if given the best possible scenario, the Virtualbox 3D acceleration is still "experimental" regardless of such status being explicitly mentioned (Windows) or not (Linux).
