I'm also using a 9700k with a 2070S and the pair works super well together for me. I haven't experienced any issues playing AC Odisey (I don't have Origins) pushing a 1440p monitor. I sometimes use V-sync or limit frames to match my 60hz monitor.
I've been folding the last week or so and it has given me a great look at my temps when pushing the computer. Much more intense than just gaming on the hardware, lol. I've upgraded fans and a bit of case modding to improve airflow. Are your temps ok when pushing it hard?