Because of all sort of issues with nvidia+wayland (e.g. can't enable hw acceleration in chrome), I decided to use my Intel iGPU as the source of video output to my monitor. Simply plugging the HDMI cable in it doesn't work - the screen remains black most of the time, if getting any signal at all.
The correct solution is bios -> internal graphic -> enable
The pitfall to avoid is bios -> display priority. Leave it at PCI 1 and don't change it to iGPU. Otherwise it still doesn't work.