Well, I should confirm what I wrote too… RawTherapee does indeed recognize and use v.4 profiles.
According to the information provided in the sRGB Profiles page, from the website you pointed to:
Display class version
The sRGB_v4_ICC_preference.icc profile is of the profile class ‘colorspace’. While ICC recommends this version is used, some applications fail to recognize colorspace class profiles. A workaround for such cases is to use a ‘display’ class version (identical in all respects except for the profile class field in the header, and the profileID value).
It turns out that both ISO22028-2_ROMM-RGB.icc and sRGB_v4_ICC_preference.icc are of class colorspace, and they are not recognized by RT. On the other hand, you have the sRGB_v4_ICC_preference_displayclass.icc v.4 profile is perfectly recognized by RT:
This is the bottom part of my output icc profiles list, taken from RT5.8
As a bonus you can see also installed the v.2 sRGB profile from color.org (sRGB2014.icc).
In short: you can use your sRGB v.4 display profile, but you have to find a ROMM v.4 profile of the class display. Or maybe better, use one of the good profiles installed by default by RT.
EDIT: well, it seems I was too lazy to fully test those profiles. On my computer, the referenced v.4 profiles are recognized as input profiles (all of them), not recognized (none) as working profiles, and only the display sRGB v.4 profile is recognized as output profile.