I'm sorry for all the confusion. Yes, it is a Fedora doubt, not an OpenWRT doubt.
First and second time I flashed a router with OpenWRT I couldn't configure it using a notebook with Fedora because it kept disconnecting after failing the connectivity check (because the router didn't have internet yet). This time I only had that notebook in hand, so I had no other option.
The thing is, when you search online for that problem, 99% of people are actually connecting to a network that was supposed to have internet, which is why I figured you guys here might have the answer.
This is a good place to start. Although the proposed solution doesn't work for me. In the end, for some reason, it slowed down the connectivity checks and gave me enough time to configure the router before disconnecting me. So in a way it solved the problem.