Don't enable fast response! From my previous experience with Dell this never worked good.
Can you expand more on:
- shrinking text - you did this app by app, right?
- folder size - do you mean finder text size in view options?
- UI (particularly interested in this)
I am using my 32" at 2560x1440, but I had to adjust the font smoothing to 1 for text to look sharp.
Also, I have noticed text sharpness looks different on Intel Mac mini and M1 Mac mini, where the text is more blurry on Intel Mac, as if Apple intentionally did not improve their font smoothing algorithm on Intel. On the M1 Mac font smoothing 2 is similar to font smoothing 1 on the Intel, and on the Intel font smoothing 0 still looks like font smoothing is not disabled. Also M1 and Intel mini have different scaled resolution options:
Mac mini 2018 Intel:
1920x1080
2560x1440
3008x1692
3360x1890
3840x2160
M1 Mac mini:
1504x846
1920x1080
2560x1440
3008x1692
3840x2160
You did not mention if you got the 27" or 32"?