Where to begin...??
Corexy refers to a very specific arrangement of belts and pulleys. From what I can see, your mechanism does not appear to be corexy. It looks like a standard cartesian mechanism with two motors driving the Y axis and a single motor mounted on the X axis and moving the extruder in X.
The controller has to know exactly what type of mechanism it is trying to drive. If you told the controller (using M667 or whatever your controller uses to define the architecture) that your mechanism is a corexy type and it is not, it will behave very strangely. OTOH, if your mechanism is corexy and you didn't tell the controller it was, it would also behave very strangely.
Can you take another picture from the top showing the belt layout?
Whenever you drive a linear positioning mechanism with belts, you must keep the belts tight and parallel to the guide rails. That doesn't seem to be the case in your photo.
Here's some
information on corexy layout that you may find useful. It doesn't matter if your mechanism isn't corexy- basic info about positioning pulleys and belts applies to any linear positioning mechanism.
There are a few things to know about getting things moving properly. You have to use a right-hand-rule coordinate system. The machine has motion limits that you set in the config file(s). It also has a home position that you set in the config file(s). Home is where the endstops are, so the motors must drive the mechanism toward the endstops when you issue a home instruction.
"home" does not have to be the origin (coordinate (0,0,0)) of the printer. The origin is defined by the ordinate values you assign to the home position and can be anywhere within the travel limits of the mechanism. It is especially useful to set up the center of the bed's printable area as the origin of the printer.
See here for info on setting up the origin and endstops. Assigning the origin to the center of the bed/printable area is good because it makes it very easy to use multiple slicers, and you will find that using multiple slicers is sometimes necessary. Some slicers have better support material generation, some do other things well or badly. For example, if you want to print an object using a single wall spiral vase mode and you don't want a seam in the print, you're going to want to use Cura, or a slicer other than Prusa Slicer, which has a broken vase mode and will leave a seam in the print.
Ultra MegaMax Dominator 3D printer: [
drmrehorst.blogspot.com]