Something I spotted but hadn't seen mentioned. Google mandated consent mode V2 around about the same time as the March update. I wonder if a few of the people freaking out about sudden drop in traffic are actually getting the same traffic but just aren't seeing it in GA4 because of lack of consent to behaviour measurement. On some sites I saw GA4 numbers halve, but 1st party analytics shows steady traffic
It’s possible that the mandated Consent Mode V2 update and the March algorithm update have combined to create a perception of dropped traffic in GA4. While some websites experienced a significant decrease in GA4 numbers, other analytics tools may show steady traffic. This suggests that the data being collected by GA4 might be affected by users not consenting to behavioral tracking.
The mandated consent mode requires websites to ask for explicit permission from users before collecting and using their data for behavioral analytics. This can lead to a decrease in data available to GA4, particularly if many users decline to grant consent.
It’s important to consider both the algorithm update and the consent mode changes when analyzing traffic trends. While the algorithm update may have had an impact, the change in consent mode could be a significant factor contributing to the perceived decrease in traffic in GA4.