Don’t really know about video and audio production requirements, but in general, if you want a machine that lasts long, important is to have a good CPU (of course with a suitable motherboard that supports new technologies) and lots of RAM (select motherboard that supports lots of RAM). Other components are easy to upgrade later.
Now you have 16GB which is kind of “the minimum” requirement.
I built my machine about 9 years ago with an i7 CPU and 32GB of RAM for starters. The machine is still very fast and more than adequate for my purposes (heaviest stuff is development and running virtual machines). And I have upgraded and added lots of disk space as the prices of SSDs have gone down. Currently the main things that I’d like to have are the new standard fast SSDs, but on the other hand the current SSDs are still working well, so no problem either.