Major drop in FPS on Vega 8 following MESA/OpenGL library upgrade to 20.0.8-0ubuntu1~18.04.1

I have an ASUS TUF FX505DY with a AMD Radeon RX 560X / AMD Radeon Vega 8

After an update earlier today I’ve noticed a major drop in FPS in all games.
Below is a list of all the updated libraries without those that probably have no impact on graphic performance (like pulseAudio or Firefox). It looks like multiple GL related libraries changed from version 19.2.8-0ubuntu0~18.04.3 to version 20.0.8-0ubuntu1~18.04.1.

I tried reverting them to the previous version but it seem like they have already been removed from the server :/

I also tried updating to the latest drivers (version 20.20) without success.

Any suggestions what steps to take next would be appreciated.

Edit: following my attempts to reverse the changes I somehow managed to poof most of my packages and had to reinstall my system. I’m now on a clean install of Ubuntu 18.04 and the problem persist.

Edit2: I think the update somehow messed up the setting which determines for which applications to use the discrete graphics, launching all applications in the weaker card. I can force the use of the discrete card by adding DRI_PRIME=1 before any given application. I didn’t have to prefix this for every relevant app before, and I’m still looking for a more permanent fix.

linux-libc-dev:amd64 (4.15.0-109.110, 4.15.0-111.112), 
libegl1-mesa-dev:amd64 (19.2.8-0ubuntu0~18.04.3, 20.0.8-0ubuntu1~18.04.1),
libegl-mesa0:amd64 (19.2.8-0ubuntu0~18.04.3, 20.0.8-0ubuntu1~18.04.1),
xserver-xorg-core-hwe-18.04:amd64 (2:1.20.8-2ubuntu2.1~18.04.1, 2:1.20.8-2ubuntu2.2~18.04.1),
libglapi-mesa:amd64 (19.2.8-0ubuntu0~18.04.3, 20.0.8-0ubuntu1~18.04.1),
libglapi-mesa:i386 (19.2.8-0ubuntu0~18.04.3, 20.0.8-0ubuntu1~18.04.1),
mesa-common-dev:amd64 (19.2.8-0ubuntu0~18.04.3, 20.0.8-0ubuntu1~18.04.1), 
xserver-xorg-legacy-hwe-18.04:amd64 (2:1.20.8-2ubuntu2.1~18.04.1, 2:1.20.8-2ubuntu2.2~18.04.1), 
libxatracker2:amd64 (19.2.8-0ubuntu0~18.04.3, 20.0.8-0ubuntu1~18.04.1),
libegl1-mesa:amd64 (19.2.8-0ubuntu0~18.04.3, 20.0.8-0ubuntu1~18.04.1),
libgbm1:amd64 (19.2.8-0ubuntu0~18.04.3, 20.0.8-0ubuntu1~18.04.1), 
libwayland-egl1-mesa:amd64 (19.2.8-0ubuntu0~18.04.3, 20.0.8-0ubuntu1~18.04.1), 
libgles2-mesa-dev:amd64 (19.2.8-0ubuntu0~18.04.3, 20.0.8-0ubuntu1~18.04.1),
libgl1-mesa-dev:amd64 (19.2.8-0ubuntu0~18.04.3, 20.0.8-0ubuntu1~18.04.1),
libgl1-mesa-dri:amd64 (19.2.8-0ubuntu0~18.04.3, 20.0.8-0ubuntu1~18.04.1), 
libgl1-mesa-dri:i386 (19.2.8-0ubuntu0~18.04.3, 20.0.8-0ubuntu1~18.04.1), 
libgl1-mesa-glx:amd64 (19.2.8-0ubuntu0~18.04.3, 20.0.8-0ubuntu1~18.04.1),
libgl1-mesa-glx:i386 (19.2.8-0ubuntu0~18.04.3, 20.0.8-0ubuntu1~18.04.1), 
mesa-vdpau-drivers:amd64 (19.2.8-0ubuntu0~18.04.3, 20.0.8-0ubuntu1~18.04.1), 
linux-firmware:amd64 (1.173.18, 1.173.19),
mesa-va-drivers:amd64 (19.2.8-0ubuntu0~18.04.3, 20.0.8-0ubuntu1~18.04.1), 
libglx-mesa0:amd64 (19.2.8-0ubuntu0~18.04.3, 20.0.8-0ubuntu1~18.04.1),
libglx-mesa0:i386 (19.2.8-0ubuntu0~18.04.3, 20.0.8-0ubuntu1~18.04.1)