To get the best possible performance and a stable internet connection for your PS5, it is recommended to use a Cat6 or Cat6A Ethernet cable. These cables are capable of supporting the speed requirements of the PS5, which can reach up to 2.5 Gbps. Cat6a is the most recommended as it provides the fastest and most reliable connection. However, Cat8 Ethernet cables will be a smarter investment while still yielding the same results. It is also important to consider the length of the cable, as longer cables can result in slower speeds or signal loss. It is recommended to choose a cable that is no longer than 10 meters.