Interesting.
There is a plan to do Pyrenees (possibly 2025), we used Plymouth - Stantander crossing this year for the Picos, but I wouldn't want to be stuck on the boat for two nights to Bilbao.
I'd sooner take an overnight Portsmouth - St. Malo crossing and be ready to get off the boat first thing in the morning, rested, and with breakfast in my tum. Then head for Rochefort, La Rochelle, or some other nearby town for another night, before reaching the Pyrenees the following evening. I would enjoy the ride and scenery, instead of being sat on the boat being bored to death.
My thoughts exactly - heading to Eauze in Armagnac next year, and opted for in and out of St Malo, though Bilbao would be closer

