How do I prevent sampled data being shown on my Data studio dashboard when connecting with Google analytics?

No, creating a new Google Analytics 4 (GA4) property is not necessary when moving your blog from blog.mysite.com to mysite.com/blog. In GA4, the same property can be used for tracking across different parts of your website, including different subdirectories or subdomains.

However, to ensure correct data collection, you should change the current GA4 property settings and tagging setups

To build your own audience, you should use the Audience Builder in Analytics. Here are the steps:

• In the account, go to Admin
• Open Property column and from Audiences choose New Audience
• Then select Custom Audience

The difference can be seen in the structure of the data and how the dimensions and metrics are calculated.

• Open Tags and then choose New. Finally, click on GA4 (Google Analytics 4) Event.
• Select the GA4 Configuration tag that already exists.
• Finally enter the event name.

To filter out domain traffic data from GA4 go to Property column. Then click on Data Settings and go to Data Filters. Now click Create Filter and choose Internal Traffic. Lastly, enter a name for the data filter.