Driver Nvidia 390 can't be installed with Geforce 820m

Support Graphics & Display
8

In that case you are not using PRIME.
The mentioned command with bumblebee becomes:

primusrun glxinfo | grep 'renderer string'

(note: you can also use optirun … if memory serves though primusrun was newer/preferred)

https://wiki.archlinux.org/title/Bumblebee