The simulators can be installed by installing Xcode. However, compared to previously, it's so much more cumbersome to quickly test, inspect and debug different viewports for devices now. Previously we had a set of device icons that you could click and this was great. Please bring that back.

Completely agree. Removing the device views is a major step back. It makes the whole development, inspect and debug process so much slower. Please bring back these device view buttons in Safari itself, instead of forcing people to load a Xcode Simulator for each device.