While Reddit is getting shittier by the minute, just an FYI: you can still search within a sub even if the sub tag is missing from the search bar. You need to type "subreddit:name-of-sub your-keywords", e.g. "subreddit:funny cute dog". I still use Reddit, because however shitty, there's a lot of good info on it that I can't find anywhere else (niche stuff or smaller communities). I do use a 3rd party Android client most of the times, though.