Thank you, I finally managed to have a working Vagrant version.
If anybody else is stumbling upon this thread:
, after the initial error launching I did vagrant ssh -c "sudo apt -y install linux-headers-amd64"
it first didn't help, then noticed .vagrant.yml
where the OS also needs to be changed: os: buster64
also, I found in some document that one also needs to run `vagrant vbguest
` besides installing the plugin. I also did that at some point, unsure if that helped.