Etrecheck Report came back as hard drive too slow. Any help available to help me understand the report?

Your data seems to be considered worthless, judging by the lack of Time Machine backups. (This makes dealing with the problems much easier, as the contents can be discarded and a replacement external SSD installed.) Backups are one of the only ways to indicate data is valuable. Are you running some other backup? If this is incorrect and your data is valuable, you need backups.

This is the 8 GB / HDD slow configuration. It's meant for light browsing and looking at photos and such. Yes, it's slow. Particularly on recent releases. See the previously-linked article for options. Adding an external SSD via Thunderbolt or USB 3.x is usually the least-bad cheap option, as described in the linked article.

This particular iMac is also running rather more than this iMac can manage, with Adobe, the pen tablet, Chrome, and the rest. And the pen tablet install appears corrupt, and is malfunctioning.

tbirdvet wrote:

...I have suspected you have a 5400RPM drive which is the slowest possible drive. 7200RPM drive would just be acceptable but you really need an SSD...

SSD.

Even a 15,000 (15K) RPM HDD won't appreciably help performance.

Not enough to warrant the cost and effort.

Not with 8 GB and an HDD.

The performance gap between an HDD (at 4.2K, 5.4K, 7.2K, 10K, or 15K) and an SSD is just too big.

This is the difference between ~100 IOPS and ~200 IOPS and ~100,000 IOPS.

I work with a whole lot of 10K and 15K enterprise drives.

They're glacial, as compared with an SSD. Toasty warm under load, too.

Performance:

System Load: 1.63 (1 min ago) 1.68 (5 min ago) 1.54 (15 min ago)

Nominal I/O speed: 13.69 MB/s

File system: 74.32 seconds

Write speed: 51 MB/s

Read speed: 48 MB/s

Those scores are somewhat under nominal for an SATA 3GB 5400 rpm drive. They should be in the 70-80MB/sec range, which still "feels" dreadfully slow.

This probably is not helping:

iCloud Status: 2133 pending files

Is iCloud synching turned off?

A USB3 external drive enclosure with an SATA 6GB SSD and set as the boot volume would give transfer speeds in the range of 400 MB/sec.

Changing any internals in that model is simply not worth the risk of damage (it's a sealed case) to a 9-year old computer that cannot run the latest macOS versions. The external SSD solution is cost-effective today, and the drive can be moved to a newer computer for storage or backup when you upgrade.

Did you go to Disk Utilities and try a disk repair? If you have a mechanical drive it may be slow for the newer OS. You could try an external SSD by cloning your internal drive and then boot from the external. Or you may have some app issues. Are you running any anti virus apps? If so delete that app.

Now that I have seen the report as I have suspected you have a 5400RPM drive which is the slowest possible drive. 7200RPM drive would just be acceptable but you really need an SSD. Like I and others have stated try using an external SSD which will improve the speed several times over.

Write speed: 51 MB/s

Read speed: 48 MB/s

You main drive is dismally slow. You would greatly benefit by booting from an external SSD.

We've got seven Samsung T7 SSD.s Each of our Mac has one as a standby external drive and they all operate extremely well for us.

On my 2015 iMac read speed went from 93MB/s internal HDD to 460 MB/s with a T7; the performance improvement was dramatic. I'd assume yours would seem even more so.

Assuming no hardware errors, and assuming you have current backups of any data you value...

Start here for an overview of the general issue with iMac and hard disks...

... Why is my hard disk drive iMac so slow? - Apple Community

The performance problem is particularly bad with the 8 GB / HDD configurations on recent macOS releases.

Yuuta no aneki wrote:

Could someone recommend an external SSD to use? I bought a SanDisk but couldn't get it to be bootable no matter how I formatted it, and SanDisk support said not to use it as a boot disk.

See the link that was embedded earlier, and a subsequent link embedded there:

Why is my hard disk drive iMac so slow? - Apple Community

How to Setup and Use an External SSD as y… - Apple Community

I also had issues with SanDisk. I have Samsung SSD and WD NVME drives that work fine. I'm sure others will also recommend some other brands that also work well.

I agree that SSD is much better than a mech. drive. I had an older mac that I replaced the 5400 drive with a new 7200 with a larger cache and there was a significant improvement but I agree no where close to an SSD.