Also I’m 99% sure from the legal perspective of the consent banner legislation, tracking user journeys like you describe is specifically not “essential” functionality and must be consented to.

Article 6, no. 1 lit a) GDPR:

[Processing shall be lawful] for the purposes of the legitimate interests pursued by the controller […] except where such interests are overridden by the interests […] of the data subject

I’ll say it’s at least debatable how the controller’s and the data subject’s interest should be weighed.

I know little about Doubleclick’s products. I imagine they might track users to report on site usage and navigation patters. These are things the website does have a legitimate interest in.