You are right, languages with tracing GC are fast. Often, they are faster than C or Rust, if you measure peak performance of a micro-benchmark that does a lot of memory management. But that is only true if you just measure the speed of the main thread :-) Tracing garbage collection does most of the work in separate threads, and so is often not visible in benchmarks. Memory usage is also not easily visible, but languages with tracing GC need about twice the amount of memory than eg. C or Rust. (When using an area allocator in C, you can get faster, at the cost of memory usage.)

Yes, Python is specially slow, but I think it's probably more because it's dynamically typed, and not not compiled. I found PyPy is quite fast.