In early 2019, I purchased a 1080ti secondhand, and it worked until March 2020, when it began artifacting and unable to render games properly. I put the card under extensive testing to ensure that no other parts within the system could be causing the issue, this included a new motherboard, PSU, and memory each separately installed and troubleshooted, so I then RMAed the card after the problem persisted. After receiving my new card about a week later, the issue re-occurred. I RMAed that card, and the replacement I received 14 days after that also did not function.
At this point I had given up, so I purchased a new EVGA 2080ti at Best Buy in May of 2020. It worked for 2 years excellently. About 2 weeks ago, it would not boot properly, and I again put it under extensive testing and confirmed that the card was the issue. I RMAed that card, and the one I received yesterday now has artifacting issues, less than 24 hours after installing it.
I contacted customer support over the phone to see what could be done about the issues, and they simply stated that all they could do was RMA the card once more. However, I am obviously wary of doing this because I need a functioning graphics card in order to work, and I need a card that will actually work as soon as possible; so far RMA has not been the solution whatsoever.
Does anyone have any suggestions on how best to replace the card with a working one, or what could possibly cause my cards to regularly fail?

CraptacularOne
If cards are all regularly failing in your system I'd start investigating more closely the rest of your system. What you are experiencing is not typical. Could be any number of things from your power supply not delivering stable and "clean" power to the video card to the wiring in your house or UPS used....etc. This isn't normal and continually RMAing cards only to have them fail while not changing any other variables will just result in the same outcome...another RMA. 

100% agreed.  Owned lots of cards over my life and rarely had to RMA.

Dang, that is a lot of RMA pain. 
 
However those are two different GPU lines .... One Used 1080Ti & then your New 2080Ti issue after 2 years of use
 
Where all of those GPUs - in the same PC with the same monitor & video cable ?
 
Your monitor OR the video cable to monitor could possibly have some sort of issue - bad connection somewhere ?
 
Testing in a different PC, monitor & cable - before using in the suspect PC might a good future test

First, we need to acknowledge that removing, shipping to or from, and installing, are physical processes which increase the odds of physical damage, thermal stress, electrostatic damage, or any other possible damage (x-ray?, etcetera). Some could be caused by that.
Second, we need to acknowledge that failures of components are on a probabilistic bathtub curve. This means that while your card is increasing in likelihood of failure due to age, the card you will eventually receive from EVGA is similarly increasing in probability of failure due to age. Some could be caused by that.
Third, we need to acknowledge that testing will never find all faults. Just because EVGA doesn't find a problem with a card, doesn't mean that you won't find a problem with a card received from EVGA as a RMA replacement from someone else's stepup card or RMA or whatever history it had.

thanks for update
 
glad your happy