I usually have a USB with NomadBSD closeby, in case it’s ever needed. Typically I’d use it as a Portable OS but also as a handy bootable repair kit.
In my experience, there’s never much to repair with Manjaro, however, it’s still nice to have something more than an Installer ISO available. I combined this with an instance of Ventoy to allow booting a Manjaro Installer or other ISOs from the same USB, if needed.