A couple of relatively simple options

1) scheduler job

procedure lock_all
begin
for i in ( select username from dba_users where ... ) loop
  execute immediate 'alter user '||i.username||' account lock';
end loop;
end;

and then schedule that with dbms_scheduler

2) logon trigger

create or replace
trigger TRACE_ALL_LOGINS
after logon on database
begin
  if user in ( .... ) and sysdate > date '2024-01-01' then
     raise_application_error(-20000,'Sorry your time is up');
  end if;
end;