Upgrade My iMac (2012) Hardware & Software

Hi there fellow Apple Enthusiasts..

I have heard so many opinions, but i am curious your thoughts. Below is the info, tell me... WWYD?

Apple iMac "Core i5" 2.9 27" (Late 2012) 13,2 - A1419 | 8GB DDR3 RAM

My question is, do I just upgrade the 3.5 inch HDD with a 2.5 inch SSD? Or do I upgrade by adding:

OWC 250GB AURA PRO 6G SSD

And if so, do I do both? If I add this 250 GB internal flash, does it boot from this SSD or the replacement 1TB? AND OF COURSE... Any issues running OCLP from whatever the boot drive is? This is all very new to me and I could use any help, from someone who is knowledgeable about these things.

for the record, I already have this Hardware, which should help make a decision about what is next.

(8x4 GB) 32 GB Crucial DDR3 SODIM 204 – PIN 12800 RAM

1TB Crucial MX500 2.5” SSD SATA

Home computer. For the most part it’s used for basic Internet surfing, occasional light video editing, and minimal business activities. I have a small but pretty busy, home automation and Tech company that for lack of a better term, focuses on helping people navigate through the world of basic to mid-level technology. Through this business, I also do some AutoCAD and blueprint design work.

LAST Question I promise, I wanted to run Sonoma. Any issues using migration and Time machine backup to restore the new drive? Restore the backup first? or after OCLP install.

I should also say that I have a MacBook Pro 9,2 mid 2012 that I’ve had forever, and I’ve done similar upgrades to it as well with huge success.

I know this is a lot, but i suppose thats why we are here, in search of answers. As always, thank you so much for anyone who takes the time out of their day to make mine a little easier and me a little more educated. I appreciate you.