Any tool works well to make a portfolio
Tools don’t matter that much to building your portfolio. I would just pick one that you are already comfortable with or is easy to use (see my favourites and the AI answer)
Always have an “archive” on a platform you own or pay for:
Services and tools disappear on the internet with time. So it might make sense to invest a bit of money to have a place you own (or pay for) as a backup in case the free social media platform you choose closes. Or just have it all in a PDF format on your folder as a backup.
My personal favourites
Squarespace and podia are two pretty simple tools I like to use to build websites. Squarespace has awesome templates and Podia is a great choice if later you want to build a community and share your expertise in courses, webinars, etc.
If you are a bit nerdy, WordPress can be a great choice (even if, personally, I never got to like it myself as I feel I spend too much time setting up things and less time creating my content.