Bpftune uses BPF to auto-tune Linux systems

You are not insane. You are running a distro that enables you to patch both the distro package definitions and the source code that is compiled by those definitions. Then there is the day to day stuff such as USE ...

I have a VM that was rather unloved that I ended up using git to go back in time to gradually move it forwards in time and update. It took quite a while. It started off life in the noughties and now sports a 6.10 kernel. I won't bore you further but it did take a while but the data is still there and accessible on a modern platform.

What is mad about that?

Back in the day when Gentoo was in favor, USE flags and recompiling the world could make a huge difference in performance on much slower computers with far more limited RAM, and you cloths really see the difference. After waiting week for the world to recompile, that it. These days, unless you're, a hyperscaler and need to eke that last 10% of performance our of your hardware, ain't nobody got time for that.

    emerge --update --deep --with-bdeps=y --newuse @world

I was a Gentoo aficionado for quite a while (20+ years). I'm going back too (rather slowly)

There is a lot of very decent technology in Gentoo - it literally describes what all other distros need to do, in some cases.

You mention a week of compilation - I remember the gcc 4 thing too!