alt Hacker News1440p is enough if you haven't experienced anything else. Even the jump from 4k to 5-6k is quite noticeable on a 27" monitor.
I switched to the Studio Display XDR and it is noticeably better than my 4k displays and my 1440p displays feel positively ancient and near unusable for text.
That's great for contrast, color fidelity and compatibility with the Apple Mac. But the resolution is quite overkill.