I have noticed that I get many more results searching a tag such as #Java or #Scala from https://iris.to when not logged in (using an Incognito mode window) than when logged in, I just get the results of people I follow, which is essentially nearly nobody at this point.
Try it for yourself: https://iris.to/search/%23Scala
The other trick as a newcomer to #nostr is to increase the social network distance to the max in the #iris client and set the number of people someone follows to a minimum. Otherwise, one only sees bitcoin people and no discussion on anything else.
I've found that zapddit has the best experience for following tags I've found yet. You can set up the tags you're interested in and going there will show you a feed of just those tags from all of global.
Just be careful following people through there. I think the following list gets inappropriately cached and I've seen it revert follows I've made elsewhere.
