i cant get my studio to run 4k 120hz over hdmi

According the the specs you linked for your TV set, it has FOUR HDMI inputs.

Unfortunately, all four appear to be limited to HDMI 2.0 speeds, which are limited to

4K at 60 Hz maximum over HDMI.

If the resolutions offered only go up to 60 Hz, then that is likely a limitation of the TV set.

The Mac does not rely on Windows-like side-loaded "Drivers" which are actually packages of resolutions and settings for a specific display. Instead, it goes straight to the immutable source -- it asks the display itself.

To get a Mac display to become active, you need the Mac to query the display, and the display to answer with its name and capabilities. Otherwise, the display will not be shown as present, and no data will be sent to the display. "No signal detected" is generated by the DISPLAY, not by the Mac.

This query is only sent at certain times:

• at startup

• at wake from sleep — so momentarily sleeping and waking your Mac may work

• at insertion of the Mac-end of the display-cable, provided everything on that cable is ready-to-go

• hold the Option key while you click on the (Detect Display) button that will appear in Displays preferences (from another display)

The TV HDMI-in may be limited to 60 Hz, even if the display itself is advertised as 120 Hz or even 240 Hz (that is just internal ‘upscaling’/​frame repeats). Unless the TV manual boasts other properties. What is the exact model TV?