You can confirm by looking at the “Use VMCS Shadowing” in the vmware.log (at least this still shows on version 12.2.5). If it shows {0,1} under the Host VT-x Capabilities section, that means the Intel CPU has that feature.

There would be another “Use VMCS Shadowing” that would show { 0 } under the “Guest VT-x capabilities” section if the “Enable hypervisor” option is enabled in the Processor settings. But this will always be zero as VMCS shadowing does not go beyond the host CPU level and won’t be able available at the virtual CPU of the VM. There has to be real circuitry in the CPU and cannot be made up in a virtual CPU; and that's the whole point why VMCS shadowing makes nested VMs much faster as there is no software overhead and minimises VM-exits.

<timestamp> In(05) vmx Host VT-x Capabilities:
<timestamp> In(05) vmx Use VMCS shadowing {0,1}
<timestamp> In(05) vmx Guest VT-x Capabilities:
<timestamp> In(05) vmx Use VMCS shadowing { 0 }

As for hoping for enhancements/fixes for an unsupported software version, here is my two cents.

Many companies that makes software (especially large ones and it does not get any bigger than Apple in terms of market cap and revenue) just makes it nearly impossible to have unsupported products to have any more enhancements. If a software product goes unsupported that means there is minimal to zero budget allocated (money, people, resources, support web pages no longer updated or completely removed, etc).

So even if some rogue software engineer decides to work on code of unsupported software product, he/she would have a hard time justifying it (assuming the time spent has to be reported in some timesheet/project accounting system; even if there is no accounting or truthful accounting of time spent, there certainly would be logs on source code files being viewed/changed, etc). Plus the code would have to undergo review/signoff and testing and more people will likely have to be involved. Doubtful anyone would want to sacrifice their job/career to work on an unsupported software product version.