Multiple publications vs multiple sections?

For people that had to make the decision between starting multiple publications or starting a section within the one you had already, how did you choose which was the best move? I'm thinking about starting a second publication but I'm kind of worried about the idea of having to manage promoting two different sites, especially since you can only highlight one. I feel like both of my publication ideas could technically fall under the same umbrella, although one topic is way more niche than the other. I kinda liked the idea of doing these separately because I can brand them differently, but it may just be easier to have the new, more niche idea as a section of my original. Can anyone share some pros/cons or what helped to make this type of decision? For added context, I'm kind of doing this for fun (although I'd love to build an audience, there's no massive pressure) with no monetization plans so strategy from that perscpective isn't as essential.