What to upgrade for 1440p gaming?

Hello :) I bought this pre-built PC about 1,5 years ago and I wanna make one or more upgrades to make it run games smoother at 1440p resolution. Was thinking about maybe getting a 4070, but maybe there’s something else I should look into? Any suggestions? I’m a little clueless, any help and input would be very appreciated! (Sorry a few words are in Norwegian)