The Russo Brothers' words have authority since they're the filmmakers.
Obviously, as the filmmakers, they have authority, but I wasn't arguing that he's not free. I was thinking about the
when he actually became free. The article you linked only references a tweet from the Russos that Red Skull is free, but doesn't really go into a ton of detail as to when he's free, and, obviously, they couldn't go into Endgame territory at the time of that tweet (2018). I assume it must have been when Thanos destroyed the Infinity Stones, not when he obtained the Soul Stone. My thought process is that even if someone obtains the Soul Stone, after it's used, it returns to Vormir, and there is a keeper to watch it. Thanos used the Soul Stone twice. Once to dust half of all living beings, and again to destroy the Infinity Stones of his reality. So there was no stone to return to Vormir, and no longer a need for a keeper of the Stone, Red Skull or otherwise.
Since Clint and Natasha go to alternate reality Vormir, Red Skull is also the keeper of the Soul Stone in that reality, which, I think is interesting, as it's an alternate reality. It could have easily been someone else chosen in that reality to be the keeper of the stone, yet it was Red Skull.
As a writer, I think that keeping Red Skull as a keeper in both realities is narrative shorthand for the audience to not have to process a ton more questions that the premise of the film itself already overloaded them with (and looking at how many analyses of the "time travel" in Endgame there are, I assume a lot of people were confused, despite the film having 3 separate scenes explaining it). I can roll with their explanation, as it's not something I'm particularly hung up on when it comes to plot threads in the MCU. Ultimately, the Soul Stone in "our" reality was destroyed by Thanos, and I'm much more interested in the ramifications a reality that doesn't contain Infinity Stones will have on the greater MCU.
The Ancient One's reality we see in Endgame should be fine, since Steve returned the Time Stone there. Ditto for the other realities we saw in that film (with the one exception being the reality in which Loki escapes with the Tesseract, but the Loki series is going to explore
that reality). So Steve returns the Soul Stone to the reality in which Red Skull is still the keeper of the Soul Stone. And it
has to be that reality, as the Stones needed to be returned to the realities in which they were borrowed, at the time they were taken, so Red Skull will not have been freed in that reality, just the one our current MCU is playing out in, in which Thanos obtained, then destroyed our Soul Stone. And that was the entire point of my earlier post musing over what a Steve/Red Skull reunion on Vormir must have been like. I'm sure Red Skull will pop up again. My speculation would be that he crops up again to challenge Sam and Bucky at some point. Bucky would certainly have a bone to pick with Red Skull, and isn't as amicable as Steve. Sam doesn't have a connection to Red Skull, but as the New Captain America, I imagine if Skull returns to his old ways, he'd target Sam for what he stands for.
