First off let me say I agree with your feelings on the situation. Far too many of these cards for whatever reason don't work at default settings for end users. There are likely lots of reasons including hardware, software and end user issues.
With browser issues you may find relief by going into the settings of the browser and turning off hardware acceleration.
While multi monitor support is controlled by Windows itself today, I too have experienced weird issues too. With the same setup with an RX 580 I have issues, then with my 2060 on that setup it is fine. So not sure who is to blame there.
Lastly, some users are reporting much better stability if they don't use the AMD installer that installs all AMD features and Radeon Setting and game profiles.
What some users are doing is going to device manager and updating the driver from there. You just point it to where the AMD driver uncompressed on your storage. This will install the driver only. They users are using Trixx or Afterburner to change settings. The bad there is you may not have control on all features of individual game profiles that can be nice to have.
Only you can decide what trade-offs you want to tolerate. An RMA could be worth pursuing. A exchange or return for another product might also be an option if you are still in the return period assuming you bought this retail.
As another user I feel you pain and sorry it is happening. We all just want to play games not troubleshoot an expensive purchase.
