I've bought a color LCD module DS320240CIPS-61F. But I didn't explored the documentation and examples quite thoroughly before buying.

I didn't supposed that the text drawing is so slow, and the text unpleasantly flickers when updating even if the pixels don't really change.

I need to update text information on two-thirds of display area at least three times per second.

Unfortunately, it's impossible even if I use video mode because the dimensions of the video box are limited at 255 pixels. And I haven't got enough RAM to store a whole frame in 16-bit pixel format.

Can I detach the LCD panel from the PCB and connect it directly to my MCU? Which LCD controller is used?

You can check the new contents before updating, if changed, update the screen.

This module is designed for battery powered application, so, the on board MCU is not powerful enough to achieve high refreshing rate.

The controller of the IPS panel is 9341 if you want to drive the panel directly