Sorry I must be out of the loop. Side loading on Mac seems like it's already possible? Just download with browser, Option-Click the app and open, right?
The parent comment mentioning Asahi Linux implies they're referring to Macs, and thus MacOS, not iOS. Further the article being commented on is about the Macbook.
Not for much longer: https://lunduke.locals.com/post/6304352/apple-removes-abilit...
I ran into the same error while trying to install QMK Toolbox the other day. Apple's control-freak policy over what you can and can't install is sickening.