If you have not had any problems for over a year you can eliminate the notion that you got a lemon, and since you are comfortable working on your rig I would not recommend extending your warranty. The Aurora R12 is less proprietary than the newer models, with standard ATX PSU and mATX motherboard. The front I/O is the propriety part, but the pinouts have been solutioned and published.
My R12 will be out of warranty next month and I was considering extending it. However, I tried several times on-line and it always failed. I enter my service tag, get to the warranty page, select the Premium Support monthly plan, select "add to cart". I then wind-up on my cart's page ... but it always says it's empty! After a few tries, I got frustrated and started to ask myself is it was worth it in the first place. My R12 has been working fine since May 2022. The only mod I did was updating the RAM from 16 GB to 32 GB (w/Dell approved memory). No issues whatsoever. This is one of the first computers I bought assembled simply because my "toy store" Fry's went out of business and that's where I would shop and fill my cart with computer parts LOL. So I am very much at ease with building computers but I know that DELL hardware is custom and I also read about challenges some are having. So ... am I going overboard with an extended warranty? I wonder if the failures to renew was an omen to have me rethink LOL
Is it worth it extending the warranty on a Aurora R12?