I've just purchased and set up my 2020 Q90T 65" tv. The TV quality is excellent. I've identified two issues so far. The first is regarding network speeds, and the second regarding how it detects my Apple TV. I've posted the network issue here (https://us.community.samsung.com/t5/Qled-and-Frame/Q90T-download-speed-is-slower-than-expected/td-p/...)
Regarding the Apple TV, the first time I plugged it into HDMI 1, the Q90T didn't detect it as an Apple TV. I configured it as an OTT box, set it up without issue, but at the end, the Q90T didn't see it as Apple TV. Regardless of this, when I switched to HDMI 1, the Q90T remote was able to fully control the Apple TV. Later, I went back to reconfigure the HDMI input, and this time the Q90T figured out that it was an Apple TV connecting. The Apple TV icon showed up on the HDMI input, and everything looked good. However, when I accessed the Apple TV, the universal remote wasn't able to control the Apple TV anymore. I reset the connection back to a regular OTT box, and again, the remote started working. I reconfigured the input to be an Apple TV again, and the remote stopped working again. Right now, I've reset the connection again so it's an unknown OTT box on HDMI 1. This effectively gives me full functionality, but I don't get the nice Apple TV icon on the Home screen. It's irritating, but not unmanageable. I've renamed the input, but the icon just isn't right.
I figured it would be worth sharing this in case anyone else runs into a similar issue. If anyone has any ideas on how to get this working properly, I'm all ears.
Same issue here, but I think it's because I'm running the beta of tvOS on my Apple TV now, prior to that it was recognized properly and given the logo. CEC commands still let me control them together though, so besides the logo, not a big deal. Device detection is working for all my other devices like my Switch and XBox.
I'm having the same problem (with a Q60T). The universal remote controls the Apple TV when it's listed as unknown, but when it's listed as Apple TV it doesn't work. I am not, however, running the beta tvOS.
Though I'm not entirely certain, when TV lists Apple TV as Unknown, the TV will then control it using CEC. But if the TV successfully detects it as Apple TV and adds the official icon, then I believe it'll use MBR from the TV's embedded IR Blaster. So what you can do is make sure your ATV is somewhat close to the Samsung logo before trying the device detection again. Also, make your ATV is named "Apple TV" under Settings > General > About