Strapi - react portfolio, deploy solution and custom DNS

I’m a beginner Front End dev and I’m currently planning to build a portfolio for a friend which is going to get deeper in her illustration passion. I would Like to practice my frontend skills which I earned during the last year. HTML, CSS, JavaScript and most of all, React, and it’s important to note that I have no backend skills. Finally, it would be cool, if she could add new contents, new works or new articles, by her own without coding and without passing through my operation.
After some researches I found that an headless-CMS could be a good solution, and I choosed Strapi. After trying it, I think is a good tool apklub asphalt 9 mod with an already set backend and which give me complete freedom with frontend. I tried it only for discovery pourpose, and it seems to work very well.

Now I have the last step, which is the deployment. Since is the first time I build a real website, I have no clue about this step. I’m worried about that at the end of building, I find that I have done too much choice mistakes, so that I have to restart from scratch. The information are so much and the variety is so wide, that I have no idea how to manage this part.

So, my question are:

After choosing my tech stack, I left something important which I should consider?
I noticed other solutions instead of Strapi, like Contentful or Sanity. Any suggestion about the best headless-CMS for my purposes?
About deploying and hosting, which is the best solution for Strapi that allows me to choose a custom domain? I found some solution like Netlify, digitalOcean, AWS etc. but I don’t understand until which point can I customize the domain. Is there the possibility to have, for example www.myWebSite.something instead of something like (that for sure is not the shape of their DNS, but it’s just an example).
PS. Note about Wordpress: I don’t like it and uses php which I don’t know yet.