but it is not possible to send a color bitmap with this library !!!
So, is the lack of this capability critical? (Rhetorical.) If so, your quest for a cheap
color display must continue OR
you can start downloading libraries and try and document one that works with an SD card bitmap.
Personally, since this inexpensive TFT GLCD does not
incorporate a SD card on the breakout board, I do not think there is any issue here... match the library to the hardware selected to satisfy the needs of the project.
Of course, that is just my opinion,