I just read this! (Also, I haven't wrote my own post about porfolio as I said i would...)
I am using Next. Let me share my rationale if it helps. I want to have the site statically generated. So it loads really fast. Thats the main priority for me. But I also want it to be dynamic, so it looks and feels as pro as possible (because its goal is to convince potential clients.)
Next does it by default. In contrast to plain React, which will render on the client side. Which is slow to load. And bad for SEO.
Client routing is almost trivial to do in Next, in contrast to using Create React App with React router. Overall, I will always go for Next first if I need to use React :D
Also, as far as I understand Remix is also a good option, but it is more oriented to server-side rendering (which I don't I need). It seems it has a lot of nice features that Next still doesn't. But I will probably wont use those. (I don't know enough to make a fair comparison though)
Another option i think would be Gatsby, which is SSG only. But with Next I can do SSG and SSR per page if I ever need it :D (Also, I have almost no experience with Gatsby).
I'm just too comfortable with Next. It is also extremely easy to deploy to Vercel (and well within the free tier). The only investment I needed to do is pay like $2 USD a year for my domain, and my time.
The reason I am not using plain html/css instead is because I want to add react-based interaction with framer motion. And Next is really nice for having static pages hydrated with dynamic javascript. Specifically, I want static-page transitions, which I know can be done with framer motion. I have no idea if they can be done any other way. But those don't seem trivial to achieve. I just want those in my portfolio 😅
Also if I ever need to add extra features like authentication, i can consume third party services very easily either on the client, or server side, or at build time. As far as I understand, Next.js is really really good for this last thing. (I haven't really tried though)
I'm also using Tailwind because I won't use anything else hahaah 🤷♂️
Hopefully my thinking process helps! I may be wrong or missing something though 😅
On the other hand, I think you did a much better job at the design than me XD