I can sympathize with people that have had this issue. It's never a good time for something to stop working, let alone an expensive, professional audio interface. Having recorded live concert events for almost 20 years now, I've only had a hard drive failure once which, thankfully, only cost me the first half of the show. It sucks, but things break in this world sometimes. After that experience, I started using a backup method of recording. At one point, I was even just feeding a line-in of the overall performance into a small personal MP3 player/recorder. Something is better than nothing.
I'm not saying you should always have a backup....but....if something is that critical, you should always have a backup
As for RME quality, these are complex and very compact units with thousands of electrical connections, most of them much smaller than 1mm so there will ALWAYS be a very small percentage of workmanship issues (can't really call them defects because they passed initial inspection and test). These issues result in latent failures and are hard if not impossible to predict given all the variables from user to user. When you combine that unpredictability with the unexpected supply chain shortages from the last 2+ years, it makes for a difficult situation to correct.
The fact that it seems RME is producing enough units for more and more customers to be sent replacement units instead of waiting weeks for a unit to be repaired in house, shows that they have been moving quickly to respond to the problem. This does not surprise me because I've felt that RME has the highest regard for it's customers and pride in their products.
Again, I sympathize with anyone facing this issue but I think RME deserves some praise for the way they've handled it.
Just my 2 cents.
-Steve