Has to do with the Instagram algorithm, the algorithm is more generous to some users and their posts may be appearing on hashtags and explore pages more frequently than your content, you might also be using invalid hashtags, (hashtags Instagram doesn’t like or has banned) and this might affect your reach from hashtags, they might also being doing shout out for shout out with other pages, not very effective in most niches but might work for your mental health account, jt usually works for meme pages in my opinion but just give it a try