Only convert IPA files that you own or have the right to use. Distributing converted apps, especially paid ones, is illegal.
If you have a Mac with an M1, M2, or M3 chip, you can technically run many iOS apps directly because they share the same architecture. What is a Dmg? What is in that .ipa File? - Apple Community
DMG containing IPA — no execution of the iOS app on macOS.
However,
Before attempting a conversion, it is crucial to understand what these file extensions actually represent.
Open the newly created DMG volume in Finder and drag the .app file inside.
This comprehensive guide explains what these formats are, why you might want to convert them, and the exact steps to handle them on your Mac. Understanding the Formats: IPA vs. DMG