I have 3 monitors and want to have joined only two. However it's not possible 4 me (please, advice, if I am wrong). Each time I need to unplug the cable from the 3rd one to make it working OK. Only eyefinity quick setup and all in row (and switched off one too - cable unpluggung needed). As I remember, in old drivers it was possible, but now. Please restore flexible eyefinity setup, I see, that many questions, like this, are present already
Many Users who use Eyefinity have been complaining that Advanced Settings have been removed from AMD Drivers in 2020.
This User found a way to make the Advanced Settings visible again in AMD 2020 drivers:
See if in Advanced Settings you can do the operation you want.
I want to run the 4th one separate from the 3 I'm gaming on and I have only been able to do this by unplugging the 4th BEFORE starting Eyefinity, don't understand why it can't be as simple as NVIDIA has it and really if I had none about this prior I would had just gone to the other side, haha. I now worry that that might cause problems always disconnecting the monitor for my setup.