Module development and code questions

This post https://drupal.stackexchange.com/questions/308150/how-can-i-bootstrap-my-site-from-an-external-script contains code to create a node by bootstapping Drupal from a script outside the Drupal site. The code worked with a D9 release but when run on a D9.5.1 site it fails at the code lines setting values and saving the node.

Here is the code that works which will access a specified node...

I have two php scripts within a CRUD module. The code to edit a custom table works with a url  example.com/students100/edit/?id=1, correctly retrieving the database record and placing it in the edit form. This code runs from the edit_student routing entry below: 

I am developing a custom module that has a block plugin. When the plugin runs, it sometimes adds or modifies a node. And when I call the save method, I sometimes (randomly) get an error: 
Call to a member function getStorage() on null. 
If no error occurs, the node is saved successfully.
I am using Drupal 10.4.6.

my code that causes random error:

I want have a link or even better an action link, to change a field value in an existing node. To be more detailed:

Context:
Drupal 9.5 sites (preparing to upgrade) and php 7.4
The local development environment setup with  ddev. 
Two branches: main and develop. 
Locally I use drush and composer.
I dont have drush and composer on the server.
So locally I use drush config:export and config:import to export and merge.
On the server I use the UI to import the configurations.
configuration flow

Hey Guys! I would like to share that there is an issue with my Drupal portal (connected with Apigee). This issue just happened few days ago and for some reason Apigee Connection stops working. I am still using the same connection file that I used to use so I don't know what has changed in the Login module or so on.