I was responsible for multiple RADIUS services used by millions of people every day. The existing software is slow to build with, difficult to scale and expensive. I couldn't let it go.
Step one was building the platform to run it on and make it sustainable as a business. Step two is implementing protocols like RADIUS that lack a separated compute/storage model but should really have one.
I chose C# because I know it, and build native single-file executables using AoT.
And on and on.
A stateless compute model with separation between the packet handling and the authentication logic solves pretty-much all of it.