Erm, just return a new url after the match? Get fancy with state machine like enums? Rust has everything you need here, not getting why you think this requires a framework.
> Specific management of [...]
again, match for that, map your url parts, whatever - it doesn't need a 10,000 pound gorilla when it can be done in a line or two of code
> complex regex matching
erm, regex crate?
> Django, Laravel, Rails
Yup, those are valid choices. I said it's not a framework problem necessarily.
Not a one size fits all sorta problem.
Wordpress is also a fine choice if your business is knocking out new sites for a new client every month.
But, if you're building a single product over the course of a year or two, it's not the end of the world to spend a couple weeks rolling your own auth and hook it up to transactional emails and everything else. It's just one small problem to deal with, not major in the grand scheme of things. YMMV