256 MB of graphics memory is awful. cant even run windows xp on luna theme, i want at least 512 mb, and 1gb would be amazing.

for people with windows, qemu runs even worse (the only acceleration is HAXM)
there's a build with googles fork of KVM for windows support but it froze my PC once

the ability to use whatever hypervisor you want (eg. like collabVM 2.0) by asking commands for stopping and starting vms and allowing RDP and VNC displays would be great

It's the max GPU Memory you can get from VirtualBox. Sadly it's their limitation.
We can't do anything about it: https://forums.virtualbox.org/viewtopic.php?f=9&t=81370

If you mean that it lags when moving things around from Focussed mode (when you get the VM focus from Minecraft), welp that's the max you can get from a Minecraft mod rn.

It's the max GPU Memory you can get from VirtualBox. Sadly it's their limitation.
We can't do anything about it: https://forums.virtualbox.org/viewtopic.php?f=9&t=81370

If you mean that it lags when moving things around from Focussed mode (when you get the VM focus from Minecraft), welp that's the max you can get from a Minecraft mod rn.

Using QEMU instead of Virtualbox (which I know you are working on) will fix this issue @electricgrillsareuseless .

256 MB of graphics memory is awful. cant even run windows xp on luna theme, i want at least 512 mb, and 1gb would be amazing.

In my experience, it isn't. I was able to run Windows Server 2008 R2 with some apps and stuff without any lag whatsoever. Windows 10 lags tho because RAM limitations, so 256 MB of VRAM is just enough.