Hello Alexandros, 

After analysing your Kernel panics report we have determined

Each of the panics are consistently the same:

panic(cpu 2 caller 0xffffff801fa89baa): Sleep transition timed out after 180 seconds while entering darkwake on way to sleep. Suspected bundle: com.apple.iokit.IOUSBHostFamily. Thread 0x42e11.
Failure code:: 0x8c6c3148 00000031

Last Sleep: absolute base_tsc base_nano
Uptime : 0x0000520626576cd5
Sleep : 0x00002c801de2e403 0x000000005cb92ab0 0x00002c73e0ee9f7d
Wake : 0x00002c80226b1791 0x000000005c9da24c 0x00002c80215a113e

"macOSPanicString" : "panic(cpu 0 caller 0xffffff800628915a): Sleep transition timed out after 180 seconds while entering darkwake on way to sleep. Suspected bundle: com.apple.iokit.IOUSBHostFamily. Thread 0xf4711.\nBacktracing specified thread\nBacktrace (CPU 0), Frame :

That  indicate that during a sleep sequence the machine was unable to set the power state of an item on the USB bus. 

We suspect one of these devices is causing the panics, as suggested to isolate the issue please disable them one by one, and test it.