Tonight's LH 419 IAD-FRA is G3 Y8 so that seems like an option to stay in PE and go out tonight.

The best advice is always to be proactive, and never simply accept what you're given unless it's what you want. The average agent will just be doing whatever it takes to get rid of you and move on to the next pax. You have plenty of leverage in advance to request what you need, assuming it's possible, and you won't get meaningfully made whole after the fact.