I still don't understand what this means. In Debian installing qemu is no different from installing any other package, including Virtualbox.

Like:

> edit random config files

I have no idea what config files you have to edit to run a relatively basic qemu incantation. My best assumption is that they mean libvirt, but I also don't really know what you have to edit to make libvirt work.

Since the OP is using Debian, I can check the Debian instructions for setting up a KVM libvirt setup on Debian.

https://wiki.debian.org/KVM#Installation

OK, this looks relatively straight-forward. You install packages, then you create VMs. It recommends AQEMU or virt-manager to use as a UI.

I am on NixOS because I like my coffee black, but I am kind of curious to see what the experience is roughly like, so maybe I can try to follow along in toolbox. It's not going to be identical but it shouldn't be any better of an experience than native Debian, for sure.

$ toolbox create --image quay.io/toolbx-images/debian-toolbox:12
...
$ toolbox enter debian-toolbox-12

Toolbox seems to mount some libvirt stuff in for convenience, but we want to actually run libvirtd in the toolbox container, so umount it. This doesn't need to be done on a real Debian installation.

$ sudo umount /var/libvirt
$ sudo umount /run/libvirt

Now following the Debian instructions:

$ sudo apt update
$ sudo apt install qemu-system libvirt-daemon-system
...
$ sudo adduser john libvirt

Hmm, can't start libvirtd with no systemd, since I'm not on a real Debian machine. But, I can at least manually run libvirtd. Again, this doesn't need to be done on a real Debian installation.

$ sudo libvirtd &
$ sudo virtlogd &

OK. Theoretically the next thing I need to do is install the UI.

$ sudo apt install virt-manager
$ virt-manager

From here I had to Add Connection to connect to libvirt, but using the default settings worked. Admittedly this is not intuitive, but the UI will make you do it, so it's not like you can forget to.

Now I can create VMs! They don't really run in Toolbox for a variety of reasons that I could probably work around, but it's beside the point. On actual Debian this would be the end of things. Should be totally possible to install Windows 95.

--

Interestingly though, Debian recommends another tool called AQEMU before virt-manager. I think this is just a qemu frontend, so it probably doesn't need libvirt at all. (The instructions are unclear about this, which is very unfortunate.) I wonder how easy that is to use.

$ sudo apt install aqemu
$ aqemu

W00t, this one is really easy to use. No need to connect to libvirt, I created a Windows 9x VM pretty quickly. I am mildly alarmed that the default OS option is "Linux 2.6", the latest version of Linux that is in the list, and that the latest Windows version listed is "Windows 7". Since this just sets defaults it's not so important, but it definitely hints at this not being super maintained these days. Does it still work? Can I install and run Windows 98 in it?

Thankfully, yes. I followed the VM wizard using defaults, selecting only Windows 9x. Added CD-ROM image of Windows 98 SE, added a boot floppy (actually the Japanese DOS-V boot floppy for Windows 98, since that's all I had locally, still works with some awkwardness.) Started VM. Formatted, installed. (Mostly. It's actually sitting here on "Updating System Settings..." with "7 minutes remaining". But I reckon it'll be done in a couple more minutes.)

OK, so there you go: if you would like to use qemu+KVM to install Windows 9x, you absolutely can do it using aqemu on Debian 12. No need to edit random config files or even bother with libvirt, if you don't want to.

Well, given how long this post is, it certainly doesn't do anything to disprove the notion that Qemu is less accessible and intuitive to use for ordinary users than Virtualbox, that's for sure. And to be sure, I 100% agree and empathize with the fact that it is not, because it isn't.

That said, this only caught my attention because it seemed like the OP had gotten stuck in an unusually deep rut, as I have basically only ever needed to edit configuration files with qemu when doing ridiculous things in libvirt (like PCI-e passthrough and Looking Glass and the like.) Beyond that, setup and usage of qemu is typically not too bad, with the rather large caveat that you kind of have to know what to do.