Not even sure you need any discreet notice about anything for strictly necessary first party cookies. That's my understanding of GDPR, at any rate.
That's true. Strictly technically necessary cookies do not need consent or even information with a banner. Guess it's nice to know, but probably not legally necessary.
You don't HAVE TO have a cookie banner for cookies which don't require consent.
Cookies not requiring consent :
Also, the law is about trackers, not specifically cookies: so data in local and session storage are concerned as does browser fingerprinting.