[schrototo]

This is simply not correct. You absolutely DO NOT need to obtain consent for strictly necessary first-party session cookies (such as would be used by an online shopping cart, for example, or to maintain a persistent login) [1].

[1] https://gdpr.eu/cookies/

[snowwrestler]

I didn't say "obtain consent," I said serve a cookie banner. If you are only setting essential cookies, the banner can just say "This site is using cookies," with no opt-out or preferences button. But it does need to appear.