I have a Samsung 128gb USB3 micro-thumbdrive that is totally usable when plugged into a USB3 port. It instantly starts connecting/disconnecting repeatedly. The only way to use it is to plug it into a much slower USB2 port.
I also have an old USB2 TV Tuner that refuses to work (I forget exactly why but that too was a "connection" issue) that I ended up just replacing with a PCIe card.
Like so many others, I too was told the problem was either I was doing something "wrong" or told by ASUS that my "motherboard needs to be RMA'ed.")
So far so good, one full day into use and all of my USB devices seem operational and stable so far. The motherboard I used (TUF X570-Plus) did eliminate the need for a couple of my USB devices like WiFi and my USB DAC (onboard audio is actually excellent, unexpectedly). I have a USB 3.0 external 2Tb Western Digital HDD, a mouse and a keyboard now.
I did test with ALL of my USB devices, even the useless now ones to see if any would drop out under usage, but they all performed normally. I'm probably not pushing the USB bus hard enough, not even the HDD. I think I'm gonna be okay.