Haven't used railway but my understanding is they are something similar to Heroku. Fly.io has been pretty great for tiny projects in that niche.
For Vercel if your nextjs site can be compiled statically you could probably throw it up on almost anything. We've self hosted before which is pretty straightforward but you lose a lot of the image optimization stuff unless you go deep into setting up open next.
For Vercel if your nextjs site can be compiled statically you could probably throw it up on almost anything. We've self hosted before which is pretty straightforward but you lose a lot of the image optimization stuff unless you go deep into setting up open next.