Smallest tablet to start for dashboard webapp?

Aloha community, i would like start a webapp. The smallest device would be a 11 zoll Tablet to desktop. Smartphone device wouldn’t be make any sense for dashboard in this app. What frame i have to choose? I saw something like 1280x800 10.5 zoll this would be working on my own tablet, i have Galaxy Tab S9 im not sure but it is 10.9 zoll 2560x1600 but it is obligatory the 1280x800 10.5 zoll? . What frame i have to use to start with smallest tablet?