I think you've found a very reasonable way how to deal with it using the NSFW toggle. If some subreddits aren't properly marked that's on them.

Btw, I think I found a bug. On mobile tapping on 'more subreddits' initially doesn't work for me. After I tap on top and then get back to the subreddit menu, it starts working.

All in all very nice, thanks for making this!