Know your audience
It starts with knowing what you design and who you design it for. The color palette considered suitable for a funky new social networking site for young cat lovers in South Asia might look very different from the colors that would be considered working well for a new financial online service for young families.
Psychology of colors
Further to the comments, the problem is because you changed the background colour in the settings: Simulate Colored Paper. If you do that, and also have the Overprint Preview enabled, this will cause the problem. You can toggle the Overprint Preview on/off by hitting Alt+Shift+Ctrl+Y
Note that the option to simulate paper is for showing what will happen if ...
Set the color mode of the image to RGB. Insert 2 adjustment layers. On the top you should have layer Hue&Saturation, option colorize=ON to set the color. Below it you have layer "Curves" to lift the black to grey.
The colorization is disabled in the next image, the curves layer lifts black to grey:
The full effect:
Flatten the image or merge ...
The warning you have circled in the example means "out of gamut for CMYK" - so I suspect you either changed the colour mode to CMYK, or you are viewing the CMYK proof colours.
Make sure you are in RGB colour mode, and switch off CMYK proofing: CTRL+Y toggles it on or off.
Here's a few things you might want to consider when picking your colours.
Make sure your information stands out against backgrounds are contrasting enough to be easy to ready.
Also with features like dark mode, you can consider the environment or time of the day your website will be used during.
Make sure your colours ...
There is one real answer and several applications/implications.
The answer is to define a standard. This means that you need to define the profiles used on each color mode (which is not the same as color space).
The applications. Now we need to apply it.
On some tests I did some time ago I have the impression that Pantone, as it is an American standard is ...