Qnap tvs-671 eol ->?

I have a QNAP TVS-671-i3-16GB (~20TB) that I use for both personal files and my backed-up disc collection. The unit lives on a rack shelf in my media closet. Streaming takes place both locally (primarily via AppleTV) and remote (smart TVs, mobile devices, Roku in the back yard, etc).

I’m low on space and am debating between just upgrading the drives or buying a new base system. Looking at the compatibility list doesn’t show processors that are significantly better than my 2015 purchase, but the -671 is now out of support.

Would you buy new drives or a new base system?

If I am going to buy a new system, I want it to last a while and support higher-res formats more easily.

Do you have recommendations on a better solution to consider? I can go with a standalone unit (like the TVS671) or a rack-mount.

I’ll probably sell the existing system if I upgrade.