Not a Surgamyfag, but it unironically makes more sense for Surge to be tsundere around Amy than Sonic. She is programmed to hate Sonic through and through, she believes he is the cause of all her pain and suffering and she wants to surpass him in every aspect. There's no "oh I actually think he super cool, but I have to keep up appearances" in all that. Amy on the other hand, isn't the one she's programmed to hate, but by all accounts she should because of how endeared Amy is by Sonic. Yet despite Amy being one of Sonic's bootlickers, Surge can't help but go along with her because how much Amy is determined to be in her space and help her accomplish her goals. It leads to a much more lackadaisical tsundere attitude.