The keyboard is not backlit. The information available indicates that this is a wireless solar keyboard with a light-powered battery, but there is no mention of backlighting of the keys in the official descriptions and tests of the product.
No, this keyboard does not have a USB or cable-only mode; it connects wirelessly via Bluetooth or the Logi Bolt USB-C receiver. It does not support a no-radio, wired-only connection mode, so it would not meet an office requirement that forbids radio (wireless) use. The keyboard is designed for wireless use only with Bluetooth Low Energy and Logi Bolt wireless connectivity.