With WandaVision under wraps (for now) and Disney+ firmly entrenched in The Falcon and the Winter Soldier, let's see how the streamer can start re-introducing the X-Men characters that don't really need films to keep the ball rolling. The can of worms was already opened with Sony's 2019 Spider-Man: Far from Home and the introduction of the Baxter Building, home of the Fantastic Four, last seen in the 2015 Josh Trank debacle. Evan Peters got to return as "Pietro" (aka Quicksilver) even when it was for a brief time and was later revealed to be artificially enhanced by Agatha Harkness (Kathryn Hahn) as Ralph Boehner. Let's see what Marvel can do beyond Loki, Secret Wars, She-Hulk, Moon Knight, and Armor Wars.
Magneto: Whether if Ian McKellan and/or Michael Fassbender choose to participate in a similar vein to Lucasfilm's Young Indiana Jones Chronicles, the story of Erik Lehnsherr was always a story born out of tragedy, vengeance, and to his fellow mutants, justice. He's allied himself on occasion with the X-Men to preserve mutantkind and certain times tried to fight alongside Prof. Charles Xavier to save the world. More often than naught, he's at odds with his best friend on whether humanity deserves to be fought for. Magneto has seen the worst humanity's offered given his persecution as a Jew during the Holocaust and in more modern times from anti-mutants.
"Better Angels" isn't a luxury he was ever really afforded and it's largely reflected in his actions. Aside from the comics canon, the McKellan incarnation attempted to turn other humans to mutants through a device in the 2000's X-Men. In the 2003 sequel X2: X-Men United, he was willing to turn his best friend into humanity's mass murderer manipulating him to target all humans with his mutant psychic powers. The Last Stand had Erik try to use Jean Grey (Famke Janssen) to overthrow humanity with her Phoenix powers. In 2011's X-Men: First Class, Fassbender's Magneto was willing to take the Cold War to the next level to a nuclear conflict.
Yes, the films really try to remind you how evil Erik is, but if Disney+ is willing to make a whole series out of Loki and placing him on some redemption story, then it's only natural for fans to know more about Erik and what he's been through. After all, the Fox films did try not once, but twice on having Erik try to live a normal life in Apocalypse (2016) and Dark Phoenix (2019) before things went predictably to shit. So I think naturally as things never went past the conceptual stage of a Magneto solo film, it could morph into something better with a TV series and a new lead actor to feature. I would allow Simon Kinberg some creative input, but don't let him be the showrunner.
Cable/Bishop: Cable, played by Josh Brolin in 2018's Deadpool 2, and Bishop, played by Omar Sy in 2014's Days of Future Past, are characters based in the future in X-Men canon. A limited series can benefit both either paired or individually regardless of it being set in the future or present day. In Deadpool 2, Cable went back in time to prevent Russell/Firefist (Julian Dennison) from scorching the earth, literally. Bishop in DOFP was only featured as a bit character as part of the last stand in the future against the sentinel threat. The new series by extension can reflect on a global threat that's gone too far as they find out how far down the rabbit hole they go. Whether if it's alone or with the help of other Marvel heroes, it's cut and dry that the espionage type of series can have long-term benefits and implications. Hell, you can even bring back Bolivar Trask (Peter Dinklage) since the character is very much alive at least in the Fox canon.
X-23: While we don't really know how long we'll see the X-Men into the MCU, there's no general hurry for an X-23 solo series with how things are spaced out right now with Daphne Keen's success on HBO's His Dark Materials. Those who followed 2017's Logan know why her performance in Hugh Jackman's swan song to Wolverine makes an X-23 series worth the wait seeing her grow up to lead a continuation of the self-enclosed dystopian future the James Mangold film started. Seeing her trying to acclimate to the modern world and hide her mutant powers would be an exercise in futility. Why bother with a young Wolverine series when X-23 has so much more room to play with knowing what already works?