Note: I’d suggest updating your email notifications first ( [avatar] > [gear] > Emails), if you go this route; I have mine set to never but adjust yours as wanted
Change your defaults in Notifications from [avatar] > [gear]
“Consider topics new when” > I haven’t viewed them yet (or other option to be less “aggressive”)
Set all categories of interest to Tracking
Click “all categories” in the upper left and go through each one of interest individually. Click on the circle in the upper right next to New Topic. Discourse does a great job of explaining the options, so adjust accordingly.
Example image below (click for full view - discourse hides overflow): The circle and tracking are boxed in green using the Announcements category as an example.