Can your recommend tools for continuous profiling? I'm mainly interested in Rust and C# on Linux.

I'm not sure if it has gotten easier. Async is harder to profile than classic threaded code using blocking IO. And for database bound code, I'm not sure which databases output detailed enough performance information.

https://grafana.com/products/cloud/profiles-for-continuous-p... can be self hosted as https://grafana.com/oss/pyroscope/

And there's also https://docs.datadoghq.com/profiler/