Anyway to adjust the volume with L activated?

I saw a video that you go to the Control Room mixer and you could adjust the volume in there. However that feature seems to have been removed in version 9.5.

Nothing has been removed.

Have a look at https://steinberg.help/cubase_pro_artist/v9/en/cubase_nuendo/topics/control_room/control_room_channel_r.html

Clicking on the Main opens the bottom section where the listen and listen dim is hidden