Simple script which installs latest version of simulators. Just list throught xcrun simctl list runtimes | devicetypes to see what fits for you. Modify as you wish.

create_latest_iOS_devices.sh

#!/bin/bash
  
# Create landscape devices

# You should run this script everytime you install new Xcode with updated iOS version, because Xcode automatically deletes the older custom created simulators.

# This just works, we need to find better solution to get the runtime. I think this should do for a while. 
runtime=$(xcrun simctl list runtimes | grep "iOS" | tail -1 | awk -F' - ' '{print $3F}')

echo $runtime
xcrun simctl create "iPad Air 2 (Landscape)" com.apple.CoreSimulator.SimDeviceType.iPad-Air-2 $runtime
xcrun simctl create "iPad Pro (10.5-inch) (Landscape)" com.apple.CoreSimulator.SimDeviceType.iPad-Pro--10-5-inch- $runtime
xcrun simctl create "iPad Pro (12.9-inch) (Landscape)" com.apple.CoreSimulator.SimDeviceType.iPad-Pro--12-9-inch---2nd-generation- $runtime

# The other devices are not necessary to add, because they are packed up with Xcode itself and always update at latest version of iOS.