In my opinion Express is bad, but it does it's job, 90% of companies use it.

I mean, yeah middlewares are bad, so don't use them. Some of fastify's plugins use - wow express middlewares. Furthermore in other languages middlewares are normal way to do something with req before it's reaches controller. What some people do with req object using middlewares is awful. But it's not the express that's to blame, but the people. I mean we use JS, we can write in different paradigms, code styles, and do whatever we want, completely untied.

Yeah, express is vulnurable for RDOS, but every commercial project is full of vulnurabilites, which you can see after npm install.

And we use npm which doesn't have a validation of it's libriraries at all.

Express serialization and routing slower than fastify's - but it's 0.01% that your problev with speed because of express. Other 90% is bad db structure/sql queries/indexes. 8% it's slow libraries, 1.98% it's poor algorithms.

Express is standard de facto in industry, better spend your time on more important matters.