If you also use the CPU Manager feature and request an integer number of cores, yes. Then for example if you request 3 cores your process will be pinned onto 3 specific cores and nothing else will be scheduled onto those cores, and CFS will not throttle your process.
QoS classes are only used "to make decisions about scheduling and evicting Pods." It still uses the Completely Fair Scheduler, which is where the problem came from (as far as I understand).
https://kubernetes.io/docs/tasks/administer-cluster/cpu-mana...