Wait for render to end to continue a For Loop

Question

I'm very new to python and programming so I brute forced myself into writing a script but I have been stuck for days and just can't solve this issue.

My script imports a set of 3 svg files, sequentially, applies some transformations, render and save the final image, delete the collection. Then do the same transformations to the next file and so on. But I am having problems with the render part. It works well for one object (if I run it outside the loop), but as soon as I run it as part of a for loop, Blender either closes, or freezes, or I get errors. I have tried some things with the handlers but can't find a solution.

The script is pretty long as I am new, and it uses a couple of text blocks as modules where I wrote the functions. Is it OK if I share a schematic of it?

What it does is something like this:

files = [file1, file2, file3]
for file in files:
  importSVG(file)
  #Applies the transforms to the objects that belong
  #to a collection that matches the file name
  doTransformations(file)
  #Render, save image and the collection is deleted
  #with a function added to the handler
  renderSaveImageDeleteColl()

I am going to try to decypher if this answer can be the solution but it's too complex for my level.

Edit: Simplified the scene. I have 5 cubes. What I want the script to do is to render a picture of each single cube. But I end up with a single render of cube 5.

import bpy
cubes = []
folder = "C:\Users\User1\Desktop\Blender Test\TestRenders\"
filePath = ""
for obj in bpy.data.objects:
    if obj.name.startswith("Cube"):
        cubes.append(obj)
        #Hide all objects from render
        obj.hide_render = True
a = 1

for cube in cubes:

    #Show current object
    cube.hide_render = False
#Set file name
filePath =  folder + "Cube" + str(a)
bpy.context.scene.render.filepath = filePath    

#Render an image of the current object
bpy.ops.render.render("INVOKE_DEFAULT",animation=False, write_still=True)

#Hide the object again
cube.hide_render = True    
a += 1

Is there a standard method to use in order to let the loop continue once the render is finished?

Thank you and apologies for my convoluted post.