There is a large amount of what _might_ be described as astroturfing on the part of vercel to push Next. More charitably, vercel/the next community publishes a very large number of good tutorials/boilerplates/etc that are built on top of next.js.
Oh interesting - I haven't been on their starting page in years. I'm surprised getting started with vite isn't higher up. That takes 5 minutes and doesn't require a full framework.
That said, starting with react router or expo is probably the right call depending on the project needs. Routing is not something you want to do yourself, and react native is pretty unfriendly without expo
Maybe I'm out of touch, but I don't understand why people think it's so tightly could with the ecosystem