Problem running blender script from command line

Question

I am trying to run a python script from command line as ./blender -P my_script.py, inside the script I have the following loop:

for item in blend_files:
_cleanup()

bpy.ops.wm.open_mainfile(filepath=item)
# commands to be run
override = {'node': bpy.data.node_groups['rad_sim'].nodes['LiVi Simulation']}
bpy.ops.node.livicalc(override, 'INVOKE_DEFAULT')

but this gives me the following error:

.../modules/bpy/ops.py", line 130, in __call__
    ret = _op_call(self.idname_py(), C_dict, kw, C_exec, C_undo)
RuntimeError: Operator bpy.ops.node.livicalc.poll() Missing 'window' in context

however if I run the two commands in the interactive console within the blender it works without issues. What is the problem, I cannot understand.

---

An alternative would be to execute the commands internally in the interactive console since the environmental variables (e.g. node tree, objects, etc) are set and if I do it manually it seems to do the job. I've tried to pass a simple command print('Hello world') to be executed but I am also getting an error:

for item in blend_files:
bpy.ops.wm.open_mainfile(filepath=item)
command = "print('hello world!!')" # here I would pass the commands  override = {'node': bpy.data.node_groups['rad_sim'].nodes['LiVi Simulation']} and bpy.ops.node.livicalc(override, 'INVOKE_DEFAULT')
bpy.ops.console.clear_line()
bpy.ops.console.insert(text=command)
bpy.ops.console.execute()

but it gives me an error kind of similar as the above one:

.../2.91/scripts/modules/bpy/ops.py", line 132, in __call__
    ret = _op_call(self.idname_py(), None, kw)
RuntimeError: Operator bpy.ops.console.insert.poll() failed, context is incorrect

---

my_script.py:

import os
import bpy
import sys
def main():
filename = "path/to/.blend/file"
bpy.ops.wm.open_mainfile(filepath=filename)
command = "print('hello world!!')"
bpy.ops.console.clear_line()
bpy.ops.console.insert(text=command)
bpy.ops.console.execute()


if name == 'main':
    print('Start!!!!')
main()

print('End!!!!')
os._exit(0)

Call then ./blender -P my_script.py and in the opened blender window in the interactive console I should get the command prin('hello world!!') executed.