Correct, to a certain degree.
Specific things that require data and/or cookies to function (e.g. providing a shipping address so that your package can arrive) are exempted, obviously. But everything else is supposed to work, regardless of consent or not.
This is due to Art. 7, Paragraph 4[0,1] regarding "Freely given consent". If your only option is to consent, or not use the website, your consent is not freely given.
[0]"When assessing whether consent is freely given, utmost account shall be taken of whether, inter alia, the performance of a contract, including the provision of a service, is conditional on consent to the processing of personal data that is not necessary for the performance of that contract."
[1]https://gdpr-info.eu/art-7-gdpr/