I also think the same as you that even though Liverpool lost in the FA Cup, that doesn't mean Liverpool will also lose to Manchester United in the Premier League. In fact, I am quite sure that Manchester United will not be able to beat Liverpool in the Premier League. It's just quite unfortunate. Because while many people are starting to expect Klopp to get lots of trophies this season with Liverpool, Liverpool are actually starting to miss opportunities one by one to win trophies. Now only the Premier League and European League remain. And I hope Klopp doesn't fail to bring his troops to lift the trophy on the two remaining occasions.
It's a shame because Liverpool failed to win that match. I think Liverpool will be able to beat United easily and advance to the semifinals. But I applaud the high press that United did in that match.
Yes, Liverpool still has a chance to win the EPL and European League. To be honest, I would rather Liverpool lose in the FA than lose a League match. Because this is a crucial moment for Liverpool, City and Arsenal. One mistake will make your chances of winning the title very difficult. Liverpool also has a big chance in the European League because in my opinion only AC Milan is at the same level as Liverpool.