Dude, just wrong. Last job, we moved .Net RabbitMQ job processor that was making a bunch of async web calls nightly would handle 50k+ messages from Windows to Linux, our job processing time was cut by 2/3. In fact, first few mornings, no one believe the execution time, thought it had silently failed and Dev team manually checked it it's work. Nope, it did its job properly with less RAM/CPU.
In my personal experience dealing with .Net 6+ (Mostly 8 now), Linux destroys Windows in performance running .Net workloads hands down 95% of the time. This lines up with Microsoft .Net team advice, every time the topic comes up "Windows or Linux?" They say "Linux, it's easier to deal with and performance is better."
You can see some benchmarks here FROM 2017: https://robertoprevato.github.io/Comparing-Linux-hosted-to-W... where Linux is beating out Windows in Async web workloads. That's only gotten better since years have gone on.
In my personal experience dealing with .Net 6+ (Mostly 8 now), Linux destroys Windows in performance running .Net workloads hands down 95% of the time. This lines up with Microsoft .Net team advice, every time the topic comes up "Windows or Linux?" They say "Linux, it's easier to deal with and performance is better."