Dell 27 curved gaming monitor 165hz 1440p questions

I recently bought a new monitor - Dell 27 curved 165hz - which I intended to use as a second monitor on my laptop. However, I saw that with the hdmi cable that I got the monitor will only run at 120hz (checked with ufo fps test) even if I set it to run on 144hz on nvidia control panel. 120hz is also the refresh rate for my laptop. As for ports, on the laptop I have a hdmi 2.0 port and an usb c port (usb3.2 gen1) which I read that cannot be used to connect external display devices :(. Now the question is why is my monitor running 120 hz instead of 144 or even the whole 165? I read that hdmi 2.0 should be able to do 240hz at 1080p.