There is an explore button down the bottom of the app, you can search in there. To be fair I mostly just browse top.posts at the moment and haven't really started to compile a list of sub subscriptions
I get your point, and I'm not saying that boost is the panacea of client possibilities, but here are my experiences with other clients (I'm also happy to be corrected if these gripes are resolved):
The web interface.
No ability to customise default views, when i go to all, it keeps loading shit as in trying to read it as new posts are added. Frustrating and I did not engage in the platform
Jerboa, buggy as hell. Constantly crashing. Unusable.
Connect. Good browser, but every time you comment you get punished by losing your place. No read tracking.
Sync. Does almost everything I want. Some ads, wish it would hide read posts when I come back later.
I'm a much more valuable member of the Lemmy community because I use sync.
If there is another client that's more betterer let me know and I will check it out.