I am confused as to how to determine which color space to use for online tech collateral (RGB vs CMYK.)
Thank you for your time to read and respond.
If it's online keep it RGB. You will never get the exact same colours across monitors.
You don't need a separate CMYK version, you can convert from CMYK via the PDF export options.
RGB has a different gamut to CMYK which means basically that sometimes RGB values and CMYK values match and sometimes they don't.
To be precise: sRGB is the specific color space you should target as your destination color space when you export that online/onscreen PDF.