Color management within a document

I am working on a document in InDesign that is ultimately destined to be a PDF to be viewed on-screen.

Also set the document’s assigned RGB profile to sRGB (Edit>Assign profiles...), and when you export the PDF also set the Output tab’s destination to sRGB. If you are exporting an interactive PDF all color is automatically converted to sRGB.

Test_Screen_Name isn't steering you wrong.

If making the color appear consistently onscreen is your priority, using one color model is necessary. If making your color build in appear the same way as your picked RGB color swatch is the priority, you want to use that RGB color build.

Just realize that the RGB color space can show all kinds of shades which can't be printed in CMYK four-color process printing. So the differences in the color you see onscreen in your examples is telling you something. Which is: If you print it, it's probably not going to match the deep blue RGB color build you specified onscreen.