In the future the answer may be go to <SITE-URL>, look up the HTTP server category and either read through a few one-line descriptions or just use the recommended package.
But: no matter how well-curated your site is, and no matter how quality those libraries are, and how well maintained, "batteries-included, in the stdlib, backed by a compatibility promise that the dev team is willing to uphold" carries some serious weight.
Considering that the Rust dev team is mostly volunteers, and many of the most important non-std-lib libraries in the Rust ecosystem are maintained by those same people I feel like there's less of a distinction than there is made out to be.
For me Axum should be the default recommendation because it's the least quirky option. It's also a very thin layer on top of hyper, and built by the tokio team, both of which have a very long track record.
Actix-web is a fine choice, but it's a bit of an odd duck in things like not being based on hyper, which makes it a little harder to integrate with the rest of the ecosystem.
Axum is very young (was announced <1y ago), it has good momentum, is based on hyper and built by the tokio team. On the other hand, it has few actual projects built with it, I couldn't find a guide for it like actix or even Rocket have (it has some documentation in its docsrs documentation, but it is pretty minimal). Crucial questions like how to handle configuration, integration with database, autoreload, are left to the examples at best.
I have no doubt that these things will come if the framework matures. I'm just questioning if it should be the default choice right now, as opposed to in a year.
(Btw, I would absolutely recommend against Rocket right now, even though API wise it clicked the best with me, until it gets more maintainers and development resumes)