Ethan pretty much sees captain's quarters as a place to decant, get a shower and get some clothes on.
He has a few extravagantly luxurious apartments in Veto Corp's various spheres of operation that he shares with Kyoko. The most notable is their Penthouse in TXW where the corporation operates from.
No expense spared of course, and every luxury one could think of given his wealth.
He also has a large suite on board his Archon class
VCS Heretic in case he ever has to rest in the field while the corporation is deployed on a Nomadic operation.
As for planetside estates, he still owns the title to his family's estate on the sandy dustball of Duripant IV, being the eldest child. It's frozen along with his family's sizeable list of assets given Ethan's wanted status inside the Federation.
The jewel of his collection is a large planetside estate that he calls home. A well hidden location that contains a huge beach-front two level glass fronted home that overlooks an enormous azure lagoon and forms the centrepiece of a private resort and retreat.
It was built as a birthday gift for Kyoko, somewhere they can spend time together fishing, diving, powerboating, swimming and relaxing. He eventually intends to retire there when he gets tired of blowing people up and taking their shit