You will have to ask the Arch packagers for help.
Download “Linux Portable Tar” from this page:
Extract the file.
Run the “shotcut” script (DO NOT RUN bin/shotcut).
These instructions are on the download page - but many people miss them:
Linux portable tar users : No install required, simply extract the archive and run it. You can drag the Shotcut folder to copy and move it wherever you want. If double-clicking the icon in your file manager does not launch Shotcut, open Shotcut.app, and try double-clicking the shotcut shell script. Do not try to run bin/shotcut directly. You may need to install JACK from your distribution. Here is a page that lists some required packages for specific distributions.