>>6484>POP_OS or just standard Ubuntu but it seems for installing onto a USB Manjaro might be easier just because of the installation process and less messing around.
What's the difference? Any distro can be installed on a USB, plus both of those you mentioned have simple graphical installers which will make that even easier. In this sense, what distro you choose makes no difference whatsoever.
If I were to give you tips, I would advise choosing a system with a fixed release schedule over a rolling release system. You don't want your USB system to die when you update after 3 months of no usage and have a bunch of packages break. Get something like Debian or Ubuntu/Mint/Pop. It might also be worthwhile to get a system that comes with nonfree drivers installed out of the box, in case any of the machines you plug the drive into need those. Debian offers the nonfree iso, and Ubuntu/Mint/Pop already come with those.
In any case, why would you want a USB like this for work? Do you often work in machines that don't belong to you? I understand doing this for something like Tails, but if it's just for normal usage, you'd be better off dual booting, or better yet, wiping windows and installing gnu/linux.