DOSBox runs on both Linux and Windows (and probably Mac too?); I was suggesting it since you might be able to replace the dying DOS computers with a modern system and just launch the legacy system as an application under it. (You might be able to do the same with a VM as well, but DOSBox came to mind first and may be easier to setup and distribute.)
Just a thought. If it’s not useful, feel free to disregard.
I tried booting an old Surface off a USB stick with stock Ubuntu once – probably either 20.04 or 22.04. (I tried this in June 2022 but didn’t make a note of the versions in my journal, unfortunately.) I was able to get it to boot, but I couldn’t get touch/pen controls working so I decided against replacing the OS. I didn’t have enough enthusiasm to bother experimenting with it further – I assume it probably needed the custom kernel.