In my case, I needed to run an internal company app that’s not available on the App Store, and the only way I got it working was via sideloading using Apple Configurator 2.
You’ll need the .ipa file and a trusted signing certificate. I connected my iPhone to the Mac, installed the app there first, then used a trick with iMazing to extract the IPA and try it on the Mac.
It’s a bit of a stretch, but for testing non-App-Store apps, it did the trick. Just be cautious about signing issues and provisioning profiles, it gets technical fast.