I refer to the TFT, there are some that have a chip dedicated to pixel management, it is generally incorporated into the PCB in addition to the screen's controller chip itself. The advantage is that you can implement complex graphical environments, which take the burden off the MCU.
In the EVE4 it is called a coprocessor, it is a 32-bit RISC 72 Mhz chip.
These screens are called HMI, there are several that could potentially be used in the teensy 4 or teensy 4.1, however you have to work in the libraries, since almost all of them are focused on AVR or ARM-STM32 or have their own environment programming, which has nothing to do with the arduino IDE.
Other examples are: TFT SmartGPU 2, which implement the graphics controller with a STM32F103 chip, or the 4DSystems Diablo or Picasso graphics chip, Nextion TFT, Stone TFT, etc. They are not cheap TFTs, and I have not seen at the moment any with the resolution you are looking for.
PS: a teensy with a dedicated graphic chip would be very nice