If you start on the wrong path, optimizations can only go so far. That's why Android still sucks after all those years of investments. That's why IntelliJ is stills slow as a dog, even on the most beefy modern machine. I wish Jetbrains would have written their IDE in something else.
Even code written in C or Assembly can be dog slow, it is a problem between chair and monitor, not necessary from what tooling is capable of.
IntelliJ would be still dog slow even if written in C.
Non stopping indexing files on every startup isn't something that changes with the programming language, or the slowness doing code completion on C and C++ code, despite usage from clangd.
