How are you copying the files to the My Cloud? Using Windows File Explorer? Sounds like some sort of problem with the laptop that is typically NOT caused by the My Cloud which has zero effect on your mouse/keyboard operation. Like cpt_paranoia indicated make sure your Windows 10 laptop is up to date with the latest Microsoft updates. Also visit the wireless keyboard/mouse manufacturer’s website to see if there are newer drivers for the keyboard/mouse or if their support section addresses your particular issue.
How was the desktop PC connected tot he local network? Ethernet or WiFi? Generally WiFi will result in lower speeds when copying files/data to and from the My Cloud. It is the inherent problem with WiFi. If at all possible use a wired Ethernet connection, preferably Gigabit on both the computer and network router/switch, to obtain the fastest speeds between your computer and the My Cloud. You may also want to review the following discussion which explains why you may have slow copy speeds between your computer and the My Cloud:
