When you run the code that you posted in reply #26, which LCD driver was found, or does it tell you there is an unknown LCD driver chip?
Have you tried the MCUFRIEND_kbv library? That is usable on most TFT displays. The diagnose_TFT_support example sketch included with that library can generally either drive the display, or provide enough information to get some help on here.
A large percentage of the flicker issues with any type display are caused by clearing the entire display and rewriting everything, or rewriting the display every time through the loop instead of just when the data changes. You have already avoided those problems. Oddly the flicker issue I'm seeing if I just rewrite the float number in your code is in the background illumination of my display - possibly caused by the display using a bit more current than the regulator on the UNO is capable of supplying.