Great article, Erica! On the topic of niches, I do think that you find your jam after some time. I have found that travel memoirs and spirituality are the things that seem to flow easiest and that people really engage with.
But I still consider myself essentially nicheless because I write on whatever ideas arise, which can be very random. I have no control π¬π
Otherwise, I am very much in agreement. Publications are great for the community aspect, and for tapping into a wider audience, but not all are helpful with that. You have to choose wisely.