The CMYK gamut fits entirely into the RGB gamut. So, every color possible with CMYK is also possible with RGB. You won't get "clipped" colors moving from CMYK -> RGB.
Vice versa is not true. RGB -> CMYK will possibly "clip" colors due to the smaller CMYK gamut.
[ image from: https://www.myprintsouth.com/ ]
In general, this comes down to how finicky you are about color. For most, just exporting a CMYK document to PDF and setting the output intent to RGB is sufficient.
I create a ton of CMYK documents for press and merely export directly to an RGB PDF for email/web distribution. I've never had a reason to complain or to specifically build RGB documents.