Most C binaries usually do not contain everything needed for their execution. It would make them too platform-specific. What most c programs do is that they use standard c library from platform for low-level things and communication with the system like memory allocation or stdin/stdout things, for example.
It is easy to install another shell indeed, but it is quite difficult to configure it. While installation of DE is usually done with just one command.
And you can use linux without DE, but not without shell. Many distributions even do not install DE by default at all.
If you want serious optimizations - then Gentoo is your choice.
But seriously, there won't be any serious difference between distributions. What really matters here are DEs and browsers.
I would recommend some kind of lightweight window manager like i3 or dwm. If you do not want to configure everything yourself, then your choice is lxde/lxqt.
Also, you can use distros without systemd (void, artix, devuan, gentoo etc), but that does not matter that much.
Ukraine use ads for anti-putin propaganda. So the russian goverment told Google to moderate ads, or all Google services will be banned. Google decided to just disable ads in Russia completely.
Same design, different technologies. LXDE was dropped in favor of lxqt. In terms of performance both are almost the same, but in the future, when all of old code will be dropped from lxqt, it would be lighter. Also lxqt looks more modern compared to lxde.
If you want sane defaults, try lxqt. It is still a huge improvement in performance after cinnamon, but you don't have to manually configure everything like in WMs.
Basically, if you do not see any reason to switch from systemd then you should not.
The thing with systemd is that it is really big and complicated. If you just use defaults of your distro systemd works just fine, but if you want to (or have to) change something fundamental, then dealing with this monstrosity becomes a bit of pain. You basically end with the situation where you are in a war with your own PC. After some time of this, dealing with an init system that does exactly what you tell it to do feels refreshing.
There is also the part, where some init systems (sysVinit and runit) boot faster then others (openRC and systemd), but it is not that significant.
I use runit BTW. With my setup I spend much less time dealing with runit then I used to with systemd. That being said I still miss some of systemd features.
Most C binaries usually do not contain everything needed for their execution. It would make them too platform-specific. What most c programs do is that they use standard c library from platform for low-level things and communication with the system like memory allocation or stdin/stdout things, for example.