"how you position it"
Hmm... and how do I do that? What's your impression?
Sciter.JS is "an embeddable HTML/CSS/JS UI engine" and that's it.
Yes, it is possible to use it without touching native side like ElectronJS, see: https://quark.sciter.com/ , but that's not the primary use case. So far it has around 400 mln installations in embedded form as part of other products, see: https://sciter.com/#customers
If you want you can treat it as Flutter that uses time proven and familiar HTML/CSS/JS resource definitions instead of Dart. Dart is close to JS but not JS, Flutter has some DOM but not HTML DOM, it has some style system but quite rudimental one.