Best counter to ATAT spam? (TR)

Playing as the Pentastar Alignment and currently cutting through the rest of the Galactic Empire planets near my borders after taking Coruscant which I autoresolved using all of the troops I got from integrating Zsinj's Empire because it was way too cancerous with like 8 ATATs on the ground. Now I'm finding the same ATAT spam on Borleias and Bilbringi and slowing losing my sanity, what's the best unit to beat ATATS with?