Best choice for HDD iMac 21.5" late 2015

Sorry everyone-- I KNOW an SSD replacement would be the best option, but it's not my computer so that's not my decision to make!

From the title, there's a 21.5" 4K iMac, late 2015 model with 1TB Fusion drive. It's currently running High Sierra and I'm in the middle of the update to Montery.

Although it's not mine, I've got permission to update the OS to "the latest and greatest." So I'm curious: what is the greatest? The HDD is... uh... not great, but it's getting the job done, and it's otherwise a beautiful machine in great condition.

submitted by /u/Audinot
[link] [comments]