240mm AIO is @ 250w capacity. 280mm AIO is @ 300w capacity.
The 10850k under heavy loads at stock values can easily top 200+w, especially on many Z490 boards where optimized values throw Intel recommended power limits and duration out the window.
For normal gaming, you'll only hit @ 70% of max, so you'd be somewhere in the 150w-200w range at stock, well within the limits of a 240mm cooler. Using handbrake or blender and other heavy load programs, that'll change as you'd be hitting 200-220w on a 250w cooler and temps would be high as coolers loose efficiency as they get closer to saturation.
Just with a simple locked core 5.1GHz all core OC, blender/handbrake loads are hitting close to 300w. Somewhat over the top of a 240mm AIO and getting to the limits of a 280mm AIO.
Could you keep your current cooler? Sure, it'll work just fine. Should you upgrade? If you want to, can't over-cool a cpu. But thats also going to depend on your use, the loads, the values applied to the cpu, and your personal opinion on exactly what is acceptable for temps.