Thank you so much for reaching out to us, I am sorry to hear that you are running into this issue, but I would be more than happy to assist!
Based on the keyboard and trackball issue, we could be running into an issue associated with drivers. When you have a moment, could you please keep everything connected and send us the output of our diagnostic utility PlugDebug --> http://plugable.com/support/plugdebug as this will allow us to examine some log files from your system, attach them to an email and then send it to firstname.lastname@example.org with “Ticket no. 206007” inside of the subject line.
In regards to the sound via the HDMI 4K TV, when you head into Playback devices, do you have the default device set as “Plugable Audio” when attempting to output sound?
Thank you for your time,
Product Owner & Technical Support