In Star Trek: Picard, the search for Doctor Bruce Maddox is an important plotline for the first half of the first season. When he is ultimately found, he is no longer being played by Brian Brophy, who played him in The Next Generation's second season episode "The Measure of a Man," but instead a different actor. Brophy is still working, it seems, if one looks at his IMdB. The same applies for Icheb, who played a somewhat important role in the last seasons of Voyager. Manu Itriyami expressed his willingness to return to the role, so why wasn't he brought back?