That message about disabling side channel mitigations shows up only when the ULM is used instead of the ring 0 VMM as the hypervisor monitor. That means the Windows host has been detected to have Hyper-V enabled.

https://blogs.vmware.com/workstation/2020/05/vmware-workstation-now-supports-hyper-v-mode.html

There is no advanced options in VMware Workstation Player. To disable the side channel mitigation, shut down the VM and add the following to the VM vmx configuration file.

ulm.disableMitigations = "TRUE"