Unable to apply CKEditor 5 with collapse text, current build requires the following elements...

Problem/Motivation

Applied this patch #3331979-3: Not compatible with CKEditor 5
Saving CKEditor 5 as new text editor shows error message when attempting to save. Issue may be with Collapse Text module ignoring html tags despite being listed under manual editable tags?

Steps to reproduce

1. Enabled CKEditor for Admin, Content Editor, and DERep Importer roles
2. Check the following boxes:
- Collapsible text blocks
- Convert URLs into inks
- Tooltips with nodes (First match only, Tooltips and Links)
- Track images uploaded via a Text Editor
- Image Resize Filter: Resize images based on their given height and width attributes
4. Uncheck "Limit Allowed HTML tags and correct faulty HTML" & "Correct faulty and chopped off HTML"
5. Try saving

When a tag listed in the error message is added to source editing (<br> for instance) an error message says the tag is already supported by enabled plugins.

Error message and current source editing tags are attached.

Proposed resolution

Remaining tasks

n/a

User interface changes

n/a

API changes

n/a

Data model changes

n/a