I may be in the minority here, but my router has been stable for more than 3 months. I have also updated to the new firmware without any issues and it's been stable so far. I tend to think now that...

There's a new firmware update 1.1.0 available via the Thether app. I am in Russia, so I guess Europe is a go. Let's see how it performs.

@attilab Yes, it's really weird how random this seems to be. Mine has these fits of 5Ghz deficiency for a day or two, but then it suddenly fixes itself and works without an issue for weeks!

So I kind of gave up, switched to 2Ghz and stop caring. I never installed the beta or anything, but now I checked again and it seems that it fixed itself. The 5Ghz channel is back to its original...

@Laagkeet It may be a dumb question, but why doesn't the newly released (March 2020) firmware address the issue, but Dec 2019 beta firmware does?

@Ben-Noon I'm not sure I want to be a beta-tester. I work from home, and if I lose access to the Internet, I am screwed, so I'd rather not risk it and wait until the next update.