I haven't played Eternum yet so I cannot compare to it, but I can recommend Mist. It's another AVN here on itch. It was quite good. One of the few AVNs I've managed to finish, and wanted to pay for. The cast is small, (literally 6 characters, counting the MC) which leads to everyone having a great amount of depth. Some of the scenes, especially towards the end, are very emotional and investing.