Issues when using other apps

When I try to open Spotify or some other app (but not all apps) the whole OS gets really slow and unresponsive. When I use safari/firefox/sublime text it doesn't do that.
This doesn't seem like an issue when I am not using the eGPU with external monitors

Setup: MacBook Pro 2018 15" with HP OMEN Accelerator and two external monitors with a GTX 1070.

