Since you’re using an external monitor, you probably want to follow this like I do: NVIDIA Optimus - ArchWiki
I have three external monitors connected to my hybrid Intel + NVIDIA laptop: DP, HDMI & Thunderbolt 4. The former two are connected to the discrete NVIDIA card and the latter are connected to the integrated Intel GPU.
I created a split package for all use cases based on the aformentioned Arch wiki article. You can try it out if you’d like by following my README, install it and reboot after.