He addressed that issue, and the fact that poll watchers were kept too far from the vote counters to see what they were doing. The latter issue was subsequently rejected by the Pennsylvania Supreme Court in a separate case, where they interpreted the Pennsylvania statute to mean that poll watchers had to be in the same room, but not necessarily close enough to see anything. So Giuliani's federal case is down to the unequal treatment issue.
Was he referring to mail-in ballots being received after 8 p.m. on election day? That issue doesn’t pertain to voter fraud. That issue is about whether the state Supreme Court violated the constitution in extending the deadline past 8 p.m. on election night.
That issue is the subject of a separate case pending before SCOTUS, who have been sitting on it for weeks without deciding whether or not to hear it. Justice Alito did issue an order requiring ballots received after election night to be segregated, in case SCOTUS eventually decides to invalidate them. Pennsylvania officials say there were only about 3,000 of those ballots, so (assuming that's true) they wouldn't be enough to switch the results.
And, how many late ballots might have been mixed in with regular ones in violation of Alito's order? We'll probably never know.