After I performed the following commands to fix an issue (which you can find here), the qubes no longer start, including service, app and disposable VMs:
sudo lvresize --size 40G /dev/qubes_dom0/root
sudo resize2fs /dev/mapper/qubes_dom0-root
In dom0, an error occurs saying something about an internal error: libxenlight couldn’t create the domain, followed by the name of the qube.
Note: I use Dasharo with Heads, so of course I updated the checksums. After that, I booted “Qubes_(R4.3),_with_Xen_hypervisor” from the boot options. Since then, I have had this problem.