Therefore also your statement regarding booting from a stick. You should look into virtualization. You can use it for something like this.
@0x0001, you don’t need 3D, you don’t need 256 MiB. For simple 2D output without hardware acceleration (2D acc doesn’t work in VBox for Linux VMs anyway) not even 128 MiB. The native GPU is also unimportant without passthrough. The GPU is virtualized no matter how fat the native GPU is.
These are the kind of basics one should have.
1920 x 1080 x 24 bit = 6075 KiB ≈ 6 MiB
Choose VBoxSVGA, not VMSVGA!
Here I have booted endeavouros 2019-12-22 live in a VBox 6.1.1-135531 VM. VBoxSVGA, 128 MiB (default) video mem. 1920x985 (view in a window) has been set automatically, I could also set FHD.
Apart from that, you should not worry too much about resolutions for such a live test in a VM. When endeavouros is installed in the VM, you install the guest additions (drivers for virtualized devices GPU, SPU, NIC etc.) and that’s it.