Re: Debian 10, Buster, it’s just the current version of the underlying Linux distro the Gameshell is built on, updating all the tools etc to current version, ready for the “future”. It’s not necessarily the best thing in the world to update just for fun, since a lot of what the Gameshell is built on could be dependent on older version for speed/compatibility. In a nutshell, I don’t recommend doing it unless you know your way around a command line well and what it means to update. Just wanted to check to see what your configuration was so others can help out.
There’s a fair bit of information here in this thread, and a lot of troubleshooting. It’s all up here after a lot of scrolling, but in the past, others have had a similar no screen and sound only problem. I haven’t experienced it myself, so wouldn’t know how to address it.
For now, have a look a this. This is a good start, re: starting from scratch.
Do you know how to SSH, and change directories etc from within a command line? That’s about as much as you’ll need to do in order to get this up and running.