It looks like most of the internet has decided that qemu is too scary to use directly and therefore folks tend to use libvirt and various helper utilities. I keep trying them and find them unpleasant and insufficiently useful. So I use systemd units for autostart (as described in the Arch Linux wiki page) and call qemu from there. I often use bridged networking and often pass through PCIe devices (typically GPUs, NVMe disks, and NICs).