Looks quite nice, I'm not 100% sold on having flow exposed (for, if) and plain text always escaped (wrapped in {''}), I suppose at least it encourages not having magic strings everywhere. There's some other details that look interesting like the @use feature. I like the reactive prefix concept but having had so many reactive headaches I'm interested in how this plays out. Overall it's a wait and see project for me with no clear must haves, at least right now.
I really like having to escape all the plain text. I think all the React-like code I’ve written has been at least 90% code and tags, not plain text, and the lack of escaping occasionally causes bugs (usually printing the name of a variable instead of its value).