Well you pretty much get the same behaviour with just vercel serverless functions, so installing next will just make your node_modules unnecessarily heavy

Other than that, no particular drawbacks that I can think of

What do you think about using HONO + next?

And deploy it to Cloudflare Workers?
Well thats basically what Vercel does internally for it's edge functions :q

I was thinking about dwploying to vercel, following this guide
https://hono.dev/getting-started/vercel

You want a API only Application which you create with Web Standards (Hono). To then deploy it on Vercel which itself will deploy it to Cloudflare Workers?

create a nextjs project purely for an api is totally fine and deploying it to vercel is too

you dont even need to use hono or express or anything like that

yeah you are right, I was overthinking, I will just sticky with app routes