The project you cite is super-optimized for the Prometheus use-case and data model. TimescaleDB beats InfluxDB on performance even without these optimization. It's also not possible to optimize in this way in most other time-series databases.
These scripts also work hard to give users a UIUX experience that mimicks PromQL in a lot of ways. This isn't necessary for most projects and is a very specialized use-case. That takes up a lot of the 2000 lines you are talking about.