The incident and the decision
Will Smith slapped Chris Rock during the March 27, 2022 Oscars broadcast. On April 8, the Academy announced a ten-year ban on Smith attending its events, including the Oscars. Those were separate dates: the televised incident first, followed by the organization's disciplinary decision.
Source [1]What an attendance restriction means
The Academy's statement, reproduced by Town & Country, described a restriction on attending Academy events and programs, in person or virtually, for ten years from April 8, 2022. That wording concerns participation in the organization's events. It should not be rewritten as a universal ban on acting, a criminal sentence or a statement that every previous award was revoked. Different institutions have different powers and processes.
The linked 2022 nominations guide addresses the film awards themselves, while this page explains the separate disciplinary episode. Keeping the ceremony, the winning performances and the later sanction distinct gives readers a clearer account than combining them into one undated controversy headline.
Source [2]