import bpy

class CauseCrashOperator(bpy.types.Operator):
    bl_idname = "object.causecrash"
    bl_label = "causecrash"
    bl_options = {'REGISTER', 'UNDO'}

    count : bpy.props.IntProperty(name="count", default=800)

    def execute(self, context):
        for i in range(self.count):
            mesh = bpy.data.meshes.new("myobj")
            obj = bpy.data.objects.new("myobj", mesh)

            context.collection.objects.link(obj)
        return {'FINISHED'}

def register():
    bpy.utils.register_class(CauseCrashOperator)

register()

print("1")
bpy.ops.ed.undo_push()
print("2")
bpy.ops.object.causecrash(count=800)
print("3")
bpy.ops.ed.undo()
print("4")
bpy.ops.object.causecrash(count=800)
print("5")