After 14 years, I recently discovered that my desktops, can in fact, boot from USB. Just had to find the Boot Menu!
I first downloaded the LXQt Rome x86_64 ISO from SourceForge and booted it in Live mode, to find that no LXQt Panel displayed, couldn’t do anything with it. I downloaded/booted this a second time, with the same result, so there could be an issue with that particular image (openmandriva.rome-23.03-lxqt.x86_64.iso)
Tonight, I downloaded LXQt x86_64 Build 1899 from ABF, booted from USB, the LXQt Panel displayed with this build and was surprised to see LXQt 1.3.0. I think OM is the first distro to include this.