Battle.net is very slow but the games work fine!

Hi everyone!
I switched to Pop_Os as my only OS on a Dell XPS 15 9560. I am WoW and Overwatch player and thanks to your amazing guides I managed to install both of them. The performances are amazing (even better than on Windows) when I launch the actual games. Unfortunately, when I open WoW or Overwatch and the Battle.net app loads it is very slow. My whole system slows down (even the mouse gets stuck and laggy) until I click onto “play” and the actual game starts. Unfortunately this could take a couple of minutes since - as I mentioned above - the whole system gets kind of unstable and laggy.
Any idea on how to solve this?
Thanks!

@TheCarACarn I would try starting your games without starting the Battle Net app, and see if that works better for you.

Try this:
Configure game>System Options>
Turn off “Enable Feral GameMode”