Login Time After Restart

[Fishrrman]

OP:

Can you get ahold of a USB3 external SSD?

If so, try booting to INTERNET recovery (command-OPTION-R).

Then, try to install a copy of the OS (accept whatever version the installer offers) onto the external SSD.

Then, try booting that way.
How do "boot times" look after doing that?

THE BEST external SSD would be a USB3.1 gen2 drive connected to one of the USBc ports on the back.
Samsung t7 "shield" would be a good choice.

 

[MarvinK9]

OP:

Can you get ahold of a USB3 external SSD?
...
How do "boot times" look after doing that?

I could, and I don't doubt that things will improve if I do. That's not really the issue. I want to know what happened to reduce the current boot/login experience to the absolutely disastrous level it is now, it wasn't always this way. It would be great if, given a lack of hardware failure, this could be fixed.
Properly working HDD-based systems shouldn't need more than a couple minutes to boot, not 5-10 minutes before you can even enter your password and then another 15 for the system to become usable.
We haven't identified a hardware or configuration issue yet. Getting to the bottom of the problem without giving up and investing in an additional (and relatively expensive) SSD is my goal.

 

[Bigwaff]

I don’t think there will be a “fix” other than to wipe the drive and reinstall the system with a selective restore from backup targeting Documents, etc. Avoid restore of system config files, etc. Annoying, yes, but you’ve spent too much time already banging your head on a wall.

 

[MarvinK9]

That's likely what I will do. Though I did cave and buy an external SSD which should arrive in a couple days. I will see if I can restore a backup of my current system to it and once that is working I will wipe the internal drive and copy over my data, just to see if that really does address the issue.
If it does, depending on how drastic the difference is with an external SSD vs internal Fusion Drive, I may repurpose the SSD as a shared data drive that I can plug in to my other Mac, Windows, and Linux systems.
If it doesn't, I guess the internal drive will probably just be used for big media files or something.