Short answer
HubSpot's KB: Consent Mode only works in the EEA, EU and UK if a HubSpot opt-in cookie banner shows to those visitors. If your site isn't on HubSpot, you aren't integrated with GTM or GA4 through HubSpot, or you use a non-HubSpot banner, implement Consent Mode yourself. Google set a March 2024 deadline, after which non-integrated sites could lose measured data from those regions.
1. The banner
Cookie settings in my demo portal.

2. The notice
Page integration settings in my demo portal show HubSpot's Consent Mode notice.

3. Related
Cookie banner and Google Tag Manager.