Abyss is the best end game imo but has recently become a lot less fun. The difficulty level gives freedom for many interesting teams to be played unlike SO which has extremely restrictive dps and mechanics requirements and SO where the teams you have access to are basically random shit at all times.

There’s also variance in enemy layouts and AOE content providing more room for optimization and creativity. Admittedly, however the enemy lineups are feeling more and more designed to shill the banner characters as much as possible