In T4297#135301, @franklinovitch wrote:

In T4297#87108, @Erwhann-Rouge wrote:

But then I didn't found the "Login Screen" button mentioned by franklinovitch.

Unfortunately it seems like with the new settings interface, this button has been removed.
So now you can't even fix this problem anymore.

Adding /etc/modprobe.d/blacklist.conf with the content "blacklist nouveau" resulted in Solus 4 not booting anymore on my Macbook mid-2010. I'm putting this here in case someone else considers trying this on a macbook: have a plan B.