problems with the y axis is fairly unusual.
Not a lot you can do really.
Have you got the belt at a reasonable tension ?
I printed an insert for mine as the control panel end wasn't being held square.

The best way to get the right belt tension is to use belt tensioners: https://www.amazon.co.uk/Ueetek-10-G...5889859&sr=8-5
These things are brilliant :-)

The other thing is to check that the guide rods are both level. ALso that the printer is on a perfectly flat and level surface. As the vertical gantry and the y axis cantry aren't exactly a rigid combination - having it fixed to a flat surface makes a difference.