I recently bought a 12 TB external HDD to replace an ageing and free-space-volatilising 6 TB hard drive. This external HDD is meant for user data only, though I might shift data to and fro other external HDDs as I see need. This external drive is a true extension to the internal SSD user document space, which is limited in size, so will be frequently accessed and updated. The 6 TB HDD is HFS+ formatted from a time when APFS wasn't an option for me. With the new HDD waiting, I wonder whether I should be formatting it as HFS+ or APFS.
I've read the advantages and disadvantages about APFS in this answer and based on that, I tend to want to format it as APFS, but I've also read in this article that mechanical disks run better with HFS+ due to its handling of fragmentation in the file system metadata. This is a concern shared in a question here, which @bmike refuted two years ago by suggesting to simply erase a heavily fragmented APFS disk and restore the data/install, something that I'm honestly not too keen on.
In addition, since that (first) linked answer is already 5.5 years old, I wonder if anyone has gained knowledge / experience in those years about the suitability of either file system in the long run for keeping user data.