@kaustubh.umalkar, both cookie names and trackers could be the same. You rather should be concerned about cross-domain tracking (if that’s what you are looking for) as indeed there will be different
domain_userid for the same user on each of the domain (web app).
One of the approaches is to use
network_userid which is the 3rd party cookie set on the collector domain. That is if the same collector is used the
network_userid will be the same for the same user on all three web applications. The limitation, however, the 3rd party cookie (
network_userid) is more likely to be blocked by the browser than the 1st party cookie (
domain_userid) and thus you still might be getting different IDs for the same user (if the 3rd party cookie is blocked).