Vagrant and its libvirt plugin are apparently no longer actively maintained:

• Substantially only a single commit in 2026, excluding dependabot PRs and copyright boilerplate updates: hashicorp/vagrant@b0593b6...2757db8
  • Fix Ubuntu 24.04 shutdown hang with synced folders hashicorp/vagrant#13804
• Packages seem no longer updated this year: Package not available for Ubuntu 26.04 hashicorp/vagrant#13811 Package not available in Fedora 44 repo hashicorp/vagrant#13820
• libvirt plugin has no commits since 2023: https://github.com/vagrant-libvirt/vagrant-libvirt/commits/main/

So I suggest migrating our Vagrant CI to use Lima: https://lima-vm.io/docs/examples/gha/
As a bonus, we will be also able to emulate s390x, ppc64le, and riscv64.