For a developer workstation who needs to often spin different OSs to test stuff, which one is easier to setup and use?

In my limited experience, VirtualBox takes the crown, followed by GNOME Boxes. But GNOME Boxes is too simple and misses some important features. And Virtualbox, in spite of it's amazingly easy UI, has an out of kernel module with "taints" the kernel and can cause strange issues sometimes. The Linux kernel devs complain a lot about the quality of Virtualbox kernel modules and refuse to have anything to do with it.

VMware Workstation seems to be going downhill, from kernel compatiblity issues to outright crashing the machine. The UI is very good though, when it works.

Libvirt, once Red Hat's golden goose and now thrown aside together with its sister project virt-manager seems very good until you get to setting up network. What the hell. It seems they purposely made it hard to set up networking. I'm only half joking. It feels like they went out of the way to think "how can we make it harder? This is too easy, we need to sell support so it can´t be easy enough". Trying to set a network bridge in Virtualbox and VMware Workstation (and even Hyper-V) is a breeze, but it feels like walking through lava in hell with Libvirt. And Cockpit, their now preferred solution to pair with Libvirt doesn't make it any easier. Libvirt feels like it was designed for datacenter use, not worksation use. Skipping libvirt and using qemu directly with its copious amount of flags seem easier than using libvirt networking.

LXD (and its fork Incus) seems like a good balance between features and UI, has anyone had experience with it? Can it be a good alternative to Virtualbox for development and testing purposes, for a developer workstation?

Proxmox is not relevant here because it's supposed to own the machine, to have the machine dedicated to it.