Any optical media should work just fine. There are distros small enough to fit on a CD, if you only have blank CDs and no DVDs. Just remember to write it as a disk image and not to just copy the file(s) over. It has to be written as an image.
I'm baffled that it won't boot to USB - but you're not the first person who has been unable to boot to USB. As mentioned earlier, I had a laptop that refused to boot to USB no matter what I did. It had the option in the menu, but simply didn't work - even after updating the BIOS to the newest version. I even emailed Dell (I think) several times, but it was to no avail. They offered to let me return and exchange it, but I never did. I just used optical media. That was like a decade and a half ago, in that area. So, it was still straight BIOS, with no UEFI or anything.
You can always try some other distros. I'm currently playing with http://torios.top/
in a virtual machine and it's really fast - even though I'm currently using an older computer. It'd only recognize up to about 4 GB of RAM, as it's only available in 32 bit architecture.