There was some friction between Apple saying wordpress had to install a paid feature in their free app, but they backtracked on that:

https://www.theverge.com/2020/8/21/21396316/apple-wordpress-in-app-purchase-tax-update-store

https://www.theverge.com/2020/8/22/21397424/apple-wordpress-apology-iap-free-ios-app

On the android platform, it's not just one app store. There are various 3rd-party stores available other than just google play. So, there is some flexibility.

https://www.androidauthority.com/best-app-stores-936652/

The issue is that on apple, it's just the apple store and that's it. No 3rd-party options. Apple's way, or the highway. This isn't really a new thing for apple, though. The walled garden approach is just how they've always operated. Personally, I don't like it, which is why I favor android.

However, for Epic, the Apple market is just too big for them to completely write off and ignore. I do commend them for taking a stand for what they believe is right. Most companies wouldn't take the risk to go up against apple.