LTSpice doesn't know what to do with complex Pspice models. How do resolve, "Unknown SPICE device type"?

Dear user. Your circuit diagram attempts to use an encrypted Texas Instruments Pspice based model of a switching converter. Unless you got a decrypted Pspice model from Texas Instruments, this will not work.
In case you got a decrypted Pspice model from TI, there are syntax differences between LTSpice and Pspice with a number of basic components that could create a model conversion issue. Have you tried downloading the TI publshed Pspice simulator tool? That would be my first step before doing anything else.

You model links to a Texas Instruments part

The TI simulator is not user friendly and not plug and play. LTSpice is such a superior tool and I refuse to waste my time with the TI simulator. I am purchasing an evaluation board instead.

I know it does. I downloaded it from TI's website.