Displays seem faint, pale, washed out on Samsung LS27A70

Ever since I connected two Samsung LS27A70, I've had difficulty with seeing content. Text seems to be rendered appropriately, but shadows around boxes (e.g., editable fields on a Web page) are hard to distinguish...hard? Shoot, sometimes I have to highlight an entire section to be able to locate checkboxes.

The problem seems to be more pronounced in Safari than in Firefox. It's also pretty obvious in Maps and some third party apps (e.g., 1Password). Do they all use the same rendering engine (or whatever)?

Of course, I fiddled with settings, but changing them didn't seem to make any difference. (I should note. that the light-dark buttons on my old Mac keyboard do not affect the display; also, if I change some features in System Settings, such as

I spoke with Samsung [business] tech support. The analysis was "compatibility issue." Hmmm...with a pretty well-known device and software?

Have other users had similar experiences? Anyone have suggested fixes?

Mini 2023 M2 Apple 16 Gb

Ventura 13.4.1(c)

Samsung LS27A70 27-inch at 1920-1080 (default) (I have two of these and both have the problems)

-- connected via HDMI

-- set to High Dynamic Range (if that matters)