It's a competitive space. However...
Think about the restaurant quarter of your nearest town or city (pre COVID-19, at least!). A restaurant on its own might pull in enough diners to be viable. But as more restaurants open up, the district starts to become a destination in itself. Bars start to open, and theatres and clubs follow, and more people visit. Each business is stronger for having several competing venues.
I think that the online personal finance space is similar. 'Online money making' has had a somewhat shady reputation, but as more and more credible sites emerge, the more credible the sector as a whole will become.
You'll intrinsically find your niche through the audience that you pursue, your writing style, and your individual focus. If you can't find what you're looking for then "be the change that you want to see". Hopefully your angle will help you stand out.