I'm surprised no one has mentioned VaatiVidya yet. His voice is so calm and relaxing, he's a fantastic narrator. His content is mainly lore about FromSoftware games like Dark Souls and Elden Ring.
I think there's another factor affecting your specific community growth and interaction. Here in Texas, it's still blistering hot outside. Once it cools down, many of us in the hotter locations will start geocaching again.
OP, what region are you from? I remember sushi being really cheap in Sydney and it was considered a go-to for students. But here in the States it's more expensive and (at least in Dallas and Denver) you don't really want to go to anything less than a sit-down restaurant for it.
This is a really interesting idea! It sounds like you'll need something to translate the Morse code into alphanumeric characters as you type.