You're really misrepresenting Lisp macros here, being able to rewrite syntax is only one (admittedly important) facet of these.

The real thing with CL is that the entire language is available during parsing and macro expansion and that users can hook into these steps to influence them. No artificial limitations like you get in C++'s consteval, you can do everything and anything without having to use a crappy DSL to do it.

Also, I've never found SBCL slow to compile. Have you?