The compiler is significantly slower than Java's, though.

That's the sad truth for a lot of modern compiled languages (I think Go is an exception). While I did not dig into their compiler internals, it just seems an inevitable consequence from a powerful language (Go is pretty simple in that regard). C++, Rust, Scala, Kotlin, Swift, they all have significantly longer compilation times compared to their predecessors. Probably that's the price we have to pay.

Chez compiles a 80Kloc project of mine in less than a second, and apparently that is still 2x slower than before they switched to a nanopass compiler.

There is no reason compiling things should not compile at similar speeds to chez unless you are telling your compiler to ootimise everything.

C++/ruae are just exceptionally slow and it became the new bottom line somehow. I know rust does a lot of housekeeping, but after using chez and sbcl, 45s for a 1.5kloc project is killing me inside.

Not really.

.NET Native, D, Delphi, Ada and Eiffel also have pretty fast compilers, while offering quite powerful languages.

Lets even pick Turbo Pascal 7.0 for MS-DOS, which was quite feature rich, and was able to compile very large programs in a couple of seconds.

Also Visual C++ with modules preview support, incremental compilation and linking is also reasonably faster than the FOSS alternatives.

It is only a matter how much money one is willing to invest into improving tooling support.

As far as I know Google is supporting JetBrains in making the Kotlin compiler faster.