I understand や = だ in Kansai-ben but I don’t understand what either やと or だと would mean here. I’m guessing the meaning is close to “For Japanese people that is normal so I don’t understand.” Thanks!!!
This や/だ is a copula, and と is a condition marker ("if/when"). See: Differences among -たら、なら、-んだったら、-えば, etc
Therefore this 日本人だと is interchangeable with 日本人だったら or 日本人なら. A more literal translation would be "if it were (the case of) Japanese", but your translation is also fine.