I feel like this is a safe assumption, but I assume you do most of your performance work on Windows? Since you would even focus on OpenGL at all, I have to assume that you at least spend some of your time developing on Linux.

Have you tried the AMD mesa drivers? The open source driver performance doesn't look terrible, and in my own experience, it tends to work far better for OpenGL than AMD's proprietary GPU drivers.

https://www.phoronix.com/scan.php?page=article&item=rx-5700-...