Hey there!
Lockdown ensued and I am back (Hey Susan + all) ! Thought I would try Manjaro and try Seamly (was around @ Valentina days) and have a run at making something! Unfortunately I cannot get Seamly to build from the AUR, could someone give Manjaro a whirl and see why Seamly fails? I don’t wish to use Debian/Ubuntu but don’t mind Arch/Manjaro or FreeBSD. I could give the errors if anyone is interested?
HEY MATT!!!
Great to hear from you!!! 
Yeah we’re looking into this. Apparently there’s an issue with the latest KDE desktop (used in Archlinux-based distros) and apps built with Qt GUI widgets. It’s X11 vs. Wayland graphics.
But please post the errors you’ve encountered. As always, there may be more here than we assume.
Thanks Susan! Haven’t looked at dressmaking stuff for a long long time, so hope to use this as a great opportunity to do so again! Will get on and try and build and post the errors.