According to http://ninedegreesbelow.com/photography/white-balancing-camera-jpegs.html and http://colour-science.org/blog_about_rgb_colourspace_models_performance.php, ACEScg might be the best working color space for color operations(color multiplication, etc) in krita. Rec.2020 comes close to ACEScg in terms of color operation accuracy.

http://colour-science.org/blog_about_rgb_colourspace_models_performance.php mentions Beta RGB, but elle stone doesn't provide her own BetaRGB profile.

Elle stone said I didn't have to use more saturated colors than sRGB colors just because I work on ACEScg/rec.2020 images.
I want to limit the colors to the sRGB color gamut when I work on ACEScg/rec.2020 images in krita.

Is there a fool-proof automatic way to limit the colors to the color gamut of sRGB in a wide gamut working color space such as ACEScg and rec.2020 in krita?

No. You might as well stay in sRGB if you think you should be limiting yourself to sRGB.

TheraHedwig wrote:No. You might as well stay in sRGB if you think you should be limiting yourself to sRGB.

It seems soft proofing and out-of-gamut warnings will arrive in krita 3.1.
https://docs.krita.org/Soft_Proofing
http://wolthera.info/?p=802

I think I can use soft-proofing and out-of-gamut warnings to limit the colors to the sRGB color gamut.