I had this issue at first. Make sure everything is connected to beloader and dualsense switched on. The last thing to connect is beloader to ps5. Sometimes it takes a few tries of pulling beloader out then putting back in for keyboard to respond.
Have you tried adding power to the XIM USB hub? The PS5 console port now needs to supply 5V in total to the Beloader, XIM APEX, mouse, kb & controller. That's a heavy power load for a USB port intended for a single device.
I have done the whole setup my beloader flashes green and stays green for some time then it goes off. The keyboard and mouse are not working ? Any solutions