Good luck to them. It would be great it they could offer a better service to consumers, instead of rewarding developers who will go to most popular provider anyway or be on all of them for obvious reasons.
I won't. Only third party stores I've had interest in have been F-droid for Foss apps which itself is already niche when it comes to people bothering to side load another store. Not sure how hard of a sell it is going to be to convince people to spend money on a third party store. At best I just see it for playing Fortnite.
Only way I see normal people trying it out is if Epic paid Facebook and Twitter a lot of money to only be available there.
That's because there's more to the DMA than the 3rd party app stores. It also means that Google/Apple are not allowed to charge their 30% if an app developer uses their own payment platform.
Today a company like Spotify has to pay 30% of its subscription models to Google/Apple, it it's bought through the app - same with Epic if the launched an app store for its games.
This is very predatory and monopolistic behavior, and that's why it's not illegal to do in the EU anymore. And Google opposed this because it was their biggest cash cow on Android.