Earlier quoted context omitted.
It sounds like your primary issue is that you have a severe RAM deficiency for what you're trying to use your machine for. Any OOM killer, be it the kernel's per-process one or systemd-oomd's per-service one, only exists to try to recover from an out-of-memory scenario where the alternative is to kernel panic (in the case of the kernel's oom killer) or for the system to completely lock up (in the case of systemd-oomd…
My primary issue is that a system that did an OK job at dealing with low memory situations has been replaced with a completely inadequate system. If your solution is "don't ever run out of memory" my solution is "I won't ever use your OS unless forced to." Every other OS handles this better, and my work literally requires pushing the bounds of memory on the box, whether it's 64GB or 1TB of RAM. Killing an entire cgro…
Windows is unstable even if you have more than enough memory but your swap is disabled, due to how its virtual memory works. It generally behaves much worse than others under heavy load and when various system resources are nearly exhausted.
There are several advanced and very flexible OOM killers available for Linux, you can use them if it really bothers you (honestly you're the first I've seen complaining about it). Some gaming/realtime distros are using them by default.