In X11, access to the GPU is mediated by the X server, which connects to it on start-up.  So you typically have to be running an X server that's configured to use the physical GPU in order for anything on the system to be able to access it through X11.

Normally that means installing the driver, and sometimes configuring /etc/X11/xorg.conf to use the driver.  If the machine is headless (ie no physical monitors plugged into the GPU), some nvidia drivers need this line added to the "Screen" section of the /etc/X11/xorg.conf file:

Option "AllowEmptyInitialConfiguration" "true"

WIthout that line, they'll refuse to start the X server without a display plugged into it.

Beyond that, I'm not familiar enough with RHEL to give you specific advice here on how to setup the nvidia drivers on your system, but if you've installed it properly, and then restarted X11 (or rebooted the system), and it's still not working, the only thing I can think of is that you're not running  a local X server, and you have to restart the appropriate system service.

(You can sometimes do it manually through something like "startx" or "startxfce4" , but there's definitely a supported way to do it on RHEL automatically.)

Normally the /var/log/Xorg.0.log has pretty helpful messages about which drivers X11 started and why.

At that point either you have a local X session, and you are VNC-ing into that (and 3D graphics VMware Workstation should start working), or VNC is launching it's own headless X server and you may have to configure something to get it to find the right X server if that still not working.  (I can't tell anymore if Workstation is at fault here.)