I hope your internal Hard drive is 3Tb and not 3Gb??
The built-in player "Media Center" works very well with what you want to do.
I'd also suggest reading through the FAQ thread on this forum. It has lots of tips and hints.
The patch to use the "0" key on the remote as a "stop" button is very useful and worth installing (from a networked PC).
While you say you are not worried about Kodi, I find it's library function is excellent for movies, tv and music.
It really keeps track of all your files across multiple devices and directories, including internal Hard Drive, USB hard drives and network drives.
As long as the "wrapper" is installed correctly, you use Kodi as a library and play switches automatically to the in-built player (and then back again when the video stops) to overcome all Kodi's current shortcomings with HD audio etc.
I'd also recommend updating Kodi to the latest "stable" 17.6 version and trying it out. If you have not used it before, check out the Kodi website for detailed instructions on selecting sources for libraries and use of metadata "scrapers" which give movie, music and TV episode covers and information.
Enjoy your new Q10Pro.