Finally!

Starting with iOS v17.4, Apple will allow iOS users to download and install apps through alternative app marketplaces.

"Alternative app marketplaces will function as an iOS app that is able to install other iOS apps on an ‌iPhone‌ or ‌iPad‌. Any developer can create an app marketplace, so long as they meet Apple's criteria for customer experience, fraud prevention, customer support, and more," reported MacRumors.