Module development and code questions

Hello,

I'm currently working on a module and having the folowing error

"data-error-switching-to-ckeditor5"

This error happens when I am in a "text and format editor" and when I do one of the following : 
- Add/Remove the the module icon from the toolbar
- Click on the module checkbox in the "Enabled filters" area
- Switch the "Text editor" between CKEditor5 and none

The code worked fine on drupal 9.5 with CKeditor but going to drupal10 with CKEditor5 raised this error

I have tried to include an iframe (For example:- with src="domainA.com/page1") in Domain B for accessing a page of Domain B.

But I got an error that Domain B has been blocked by Domain A due to CORs policy.

I tried to possibilities:-

 1) I have included domain B in the settings.php of Domain A as a trust_host_pattern and hence that error was not showing now.

But still I am not able to access the page, which I tried to access using iframe.

2) I have tried to enable CORs settings in sites/default/services.yml like below:-

Hello,

I'm using Acquia site studio, and I don't have much experience.

Just a tip, if you didn't know: Drupal contributors with 35 or more issue credits gained over the past year can get a free PhpStorm license. See Free PhpStorm license for Drupal contributors.

Hi, in a custom form I have several php files, both in the form and Controller folder.
From these files I need to call some functions that are the same for many. Until now I have rewritten them but to avoid errors, I would like to write them in a single file but I am not clear how to do it

Hello,

I'm having problems controlling access to nodes since I upgraded to Drupal 10. The options I had explored, by taxonomy or by content, have not yet been upgraded to Drupal 10. Any solutions?
Thank you so much.