You can run just run whole Windows with IE6 in the browser these days thanks to WebAssembly:
https://oldweb.today/?browser=ie6. It even works on my phone.
If you can make it run in a standard qemu/libvirt VM, you likely should be able to ship that VM in the browser as the site I linked demonstrates.
Only problem I see is, does it need custom hardware/drivers? If yes and you can make hardware passthrough work with qemu, perhaps you could host a VM instance on a server and ship some web UI or RDP client for users to connect to it.
I’m not very optimistic given how tightly this thing is coupled to Windows and ActiveX, but I might still give it a try just out of curiosity.