After deploying the latest version of VMware vSphere with Tanzu (vCenter Server 7.0 U1d / v1.18.2-vsc0.0.7-17449972), I noticed that the Virtual Machines running the Control Plane (SupervisorControlPlaneVM) had a constant disk write IO of 15 MB/s with over 3000 IOPS. This was something I didn't see in previous versions and as this is a completely new setup with no namespaces created yet, there must be an issue.
After troubleshooting the Supervisor Control Plane, it turned out that the problem was caused by fluent-bit, which is the Log processor used by Kubernetes. The log was constantly spammed with debugging messages. Reducing the log level solved the problem for me.