MacBook Air M1 and weird text rendering on Samsung S49A950U ultrawide

I'm running Samsung S49A950U from my M1 Air at the native resolution via USB-C cable. No issues with the resolution itself (5120x1440) or the frequency (60Hz). Using USB-C to DisplayPort gives me 120Hz. So far so good. The only thing is text clarity. I can only get crisp, sharp, well defined text in HDR modes. Switch the HDR off and the text is jagged and rough. And it's not because of M1, or because of my M1 (I tested that with an identical but brand new machine). It's the same thing with an Intel-based MacBook Pro. Also, I did not experience such behavior on Samsung G9 or a Philips ultrawide. For example, two identical characters are rendered differently in a single word. In 'off' first f is rendered as f, the second as **f**. The middle line in E is jagged, lowercase l might have the 'italics' quality to it. Turn HDR back on, and the text looks just fine. Any ideas why that might be happening? *** **Update**: Well, I returned the monitor within the 14-day grace period. Just didn't have the stamina to fight it every day and getting my eyes burned by HDR.