Have a 6-ish hour layover at FRA after a flight from IAH. Final destination is PMO where we will have a couple hour drive after landing.

Flying Lufthansa economy, so no status or upgrades.

The airport website indicates there are a few lounges open to anyone for a fee. Any recommendations for one lounge over another? We are looking for someplace we can rest quietly, maybe take a nap, and clean up a little (wash face, brush teeth, etc).

Would look at the Hyatt Place next to FRA They run a shuttle. Would able to shower, nap, eat and do what you got to do. Get some rest if you expected to be alert and drive when you get to final destination. Theres also a Hilton garden Inn between terminals 1 and 2 if you dont want to mess with a shuttle.