Desktop environment not rendered correctly in VM(archlinux Virtualbox+Vagrant)

I recently installed ArchLinux in virtualbox using official BOX, and set up budgie environment.

I started the GUI using startx command, but whole environment(including login UI) is glitched.

System locale is set to “ja_JP.UTF-8” though I’m not sure it’s relevant.
How can I solve this?

VM info:
Arch Linux on Virtualbox+Vagrant
Vagrant 2.3.7
Virtualbox 7.0.10

Vagrantfile(comment lines are omitted):

Vagrant.configure("2") do |config| = "archlinux/archlinux"
  config.vm.provider "virtualbox" do |vb|
  vb.gui = true
  vb.memory = "4096"
  vb.cpus = 2
  vb.customize [
    "modifyvm", :id,
    "--vram", "256",
    "--cpus", "2",
    "--clipboard", "bidirectional",
    "--accelerate3d", "on",
    "--hwvirtex", "on",
    "--nestedpaging", "on",
    "--largepages", "on",
    "--ioapic", "on",
    "--pae", "on",
    "--paravirtprovider", "kvm",