Good news, on my VM installing Steam and then OiS now installs the 2012 and 2015 runtimes.
Bad news, on my metal it does not, even if I reinstall Steam. Maybe it remembers it has done it before and refuses to try doing that a second time?
Further bad news, 2012 and 2015 runtimes are not sufficient to start OiS on my VM. It still complains about MSVCR120.dll and MSVCR100.dll being missing. You also need to include 2013 and 2010 redistributables. Alternatively you could investigate why you are seemingly linking to every redistributable known to Windows?
BTW, to reproduce this you can download an Edge Modern IE VirtualBox image from Microsoft which comes with a 90 day evaluation, and install Steam on it.