They recast characters in movies all of the time. There were 4 different Bruce Wayne/Batmans in the same universe. There are 2 different Hulks, War Machine, Red Skull, like 3 different Howard Starks. Prof X & Magneto were played by 2 different actors in the same movie. Nolan's Batman turned Katie Holmes into Maggie Gyllenhaal. AND Jake was going to replace Tobey Maguire when he got hurt and was having back problems. He had already started the training for it. Mortal Kombat replaced everyone damn near for Annihilation. If it was anyone else, the role would've been recast. Hell Brandon Lee died on set, movie was a hit, and the role was recast for City of Angels.
If you don't make it an issue, the audience won't care. I just find it absurd that some people believe that the role can only be played by one person.
Let's say they said we'll use a "multiverse" character. That creates more problems. First, they have barely even used it. Everyone in this multiverse flick (Dr Strange) was played by the same actor. Hell, even Spidey can be dismissed due to being different ages....but JJJ was still played by the same actor. But the bring in a new actor to be "T'Challa" but he's from another universe. How does that T'Challa fit into Wakanda? The characters already established will care about him? Nope. Not Nakia, not Shuri, not Okoye, not Wakanda.