Could you please help me understand how to properly set up Marketing Cloud ID Service if the site spans multiple domains like shown below domain.com domain.com.tr
While for the first domain the MCVID setup can be left as it is, for the second one an extra configuration has to be applied:
It is not clear how to dynamically add the cookieDomain setting when the DTM is serving pages on domain.com.tr. I presume a Data Element should be built and used as shown in screenshot, but I am not sure what values to pass in case if cookieDomain is not required. Could you clarify this?
Yes it is correct that it is required to use cookieDomain for multi-part, top-level domains where either of last 2 parts of the URL are > two characters. The "www" prefix is not required when instantiating this variable.
if you do not put cookieDomain = domain.com.tr then the cookie will be set on com.tr
You DTM configuration seems to be correct.
For the data element I will suggest you to specific custom value if domain like domain.com.tr else return default base domain. you can also return "", it will put the cookie to the default base domain, I tested and it works.