Do I believe indie devs will be worse off? Unfortunately, also yes.
If you are a solo app developer, you will now have to keep presence on all app stores out there, since if you don’t publish on one then a copycat will. Every store would have its own review processes, fee structures, billing and tax procedures. Since you would need to follow a dozen of those, as an indie operation realistically you will either go under or pay middleman companies a chunk for this—so, in the end, you’ll lose the same cut or more and we’re back to the starting point.
Furthermore, I believe you will have much less protection against plain piracy, which was a big thing in the days of yore until it was spectacularly dealt with by Apple within its mobile ecosystem.
This is why I suspect the primary interests side-loading and alt app stores on Apple devices would satisfy is large enterprises and a few opportunistic middlemen. Entities like Epic, Netflix, who will be able to generate more profit; governments, perhaps; a few publishing companies (think CDBaby for apps) will win small time; some users who don’t want to pay and want to get things for free might be able to get their way; indie devs will be worse off.