Why are the RGB values ​​of colors distorted in screenshots on a Mac?

Question

macOS

Given:
iMac Retina 5K
Safari / Chrome
HTML page with block colored #dd2d4d .
Photoshop with RGB Working Space: sRGB IEC61966-2.1 Taking a
screenshot (png). When opened in Photoshop, a prompt appears:
1) use the embedded color profile;
2) convert to working;
3) do not use the embedded profile and profiling in principle.
In all three cases, the color checked by the pipette does not match the real one (specified in the page code)
1) #cb3f51 (the value does not match, it looks almost indistinguishable from the real one)
2) #dc2d4d (the value does not match, it looks almost indistinguishable from the real one)
3) #cb3f51 (the value does not match, darker than in step 1 due to the cancellation of the color profile)
When Working Space is set to Monitor RGB or Display, the selection dialog does not appear, the final color:
#cb3f51 almost indistinguishable from the real one)
In Firefox and Opera, the situation is even more interesting. The color of the block on the page is much richer and more vigorous.
When creating a screenshot and opening it in Photoshop:
1) #dd2d4d (the value is the same , the shade is vigorous)
2) #f10048 (the value is not the same, the shade is vigorous)
3) #dd2d4d (the value is the same , outwardly almost indistinguishable from the real one, in safari)
When creating a screen from an iPhone and opening the result in Photoshop, the selection dialog does not appear, color:
#cc3f50 (even darker).
I suppose it all has something to do with the expanded color gamut of the screen.
But what is wrong here? Where is the color correct and where is it not? Where to look for the truth and how to avoid distortions?
https://jsfiddle.net/4Lowqunx/

Answer 1

Not enough information.
1. "use embedded color profile;" - which one, what is the name spelled?
2. What workspace is installed in OC?
3. What are the color management settings in FF? (about:config -> gfx.color_management)