Somehow I missed that cgroups v2 changes how CPU resources are allocated! Now instead of CPU shares, they use something called "CPU weight".
I don't know what that means exactly, but this is a nice article explaining how the conversion from one to the other is done.
https://kubernetes.io/blog/2026/01/30/new-cgroup-v1-to-v2-cpu-conversion-formula/
Looks like I have some more reading to do, lol

New Conversion from cgroup v1 CPU Shares to v2 CPU Weight
I'm excited to announce the implementation of an improved conversion formula from cgroup v1 CPU shares to cgroup v2 CPU weight. This enhancement addresses critical issues with CPU priority allocation for Kubernetes workloads when running on systems with cgroup v2. Background Kubernetes was originally designed with cgroup v1 in mind, where CPU shares were defined simply by assigning the container's CPU requests in millicpu form. For example, a container requesting 1 CPU (1024m) would get (cpu.
