A crossover rather than a replacement
Marvel's behind-the-scenes account identifies Tom Holland, Tobey Maguire and Andrew Garfield together in Spider-Man: No Way Home. The performers portray different screen versions of Peter Parker, with the multiverse providing the story's connection. Their joint appearance is therefore different from a reboot in which one actor simply takes over the same ongoing role.
The film also draws on villains from earlier Spider-Man screen stories. A familiar actor or costume can carry history from another adaptation without making every earlier movie part of one identical setting.
Source [1]Keeping film evidence separate from advance rumors
Before a release, casting speculation and carefully edited trailers can leave uncertainty about who appears. A studio's retrospective on the completed film provides a different level of evidence: it can discuss an appearance openly after the surprise has been shown to audiences. The same principle applies to Harry Styles's Eternals credits scene. A documented appearance establishes that film's event; it does not guarantee an actor's role in an unnamed future project.
Source [1]