help with Tronxy X3A P802

Have you considered and overheating driver or motor?

and that right there is about 95% of the issue. Stop being "cheap"!
If you want a decent printer that is going to run without too many issues, you need to spend a little bit more and buy something of quality.

my guess is that it has either a bad motor that is failing intermittently, or the board is getting hot and causing the driver to miss steps.
It does not take much to overheat either a board, or a motor. If you are positive the motor is not getting hot, get a fan blowing on the board and see if that makes any difference.

Sorry if I come across a bit rude, but I have seen so many people do what you did, buy cheap thinking they will learn and gain confidence, and then just give up because of all the problems with the cheap printer.

if cooling is not helping, and you swapped the problem motor to rule out that specifically, then pretty much the last possibility is with the board itself.
Does the board have removable stepper drivers?
if it does, then i would suggest swapping out the problem axis with another, and see if the issue follows the driver. If it does, then you can replace the bad stepper driver.
If it does not have removable stepper drivers, then the entire board would have to be replaced.

The correct way to do things is to do your research before buying anything. Look at the best you can afford, not the cheapest.
Find out what other people are having problems with, or not having problems with. Is there customer support for the brand? is there a solid community of users where you can get brand specific help?
Buying cheap, thinking you will learn & gain confidence from it and then later get a better quality machine is the absolute WRONG way of doing this. As you are finding out, cheap often has problems, frequently problems that cause enough frustration to give up entirely.

my other half researched for months before finally deciding what to buy back in 2015, before the glut of super cheap printers hit. He ended up buying a used Solidoodle 4 for around $400, which brought us to this community where I learned everything I possibly could about the machine we had, how to make it work right, and how to fix things when they went wrong.
We still have that printer, and it is still running on a nearly daily basis 5 yrs later. Was it the cheapest route to go at the time? nope, not by a long shot. But it was a well informed choice.