First off. Please Run all the library examples.
They will show you how to calibrate your 3.5 inch screen.
Then you can use the calibrated values in your sketch.
And yes, readers will help you.
However, you get off to a bad start when you say:
const int XP = 8, XM = A2, YP = A3, YM = 9; //ID=0x7789
const int TS_LEFT = 128, TS_RT = 916, TS_TOP = 921, TS_BOT = 88;
I know that 3.5 inch screens do not have a ST7789 controller.
Which suggests that you have not followed the advice.
Likewise, you have not posted code in a proper code window.
Which implies that you have not read the Forum guidelines.
I am quite happy to spend time with beginners. And help to get your project working.
It is these little acts of politeness that makes the Forum operate nicely.
I wash my car before it goes to the garage for its annual MOT test.
A clean car makes a happier mechanic. Less chance that it fails !!
David.