TinyMCE 4 and TinyMCE 5 reached EOL in Dec. 2020 and April 2023. CKEditor 4 reached EOL June 2023.
It looks like TinyMCE 6 is still free, even though there has been a change of license.
Use Drupal 7 backport of TinyMCE Backdrop for inspiration?
TinyMCE backport
Integrates the most recent and supported TinyMCE as alternative WYSIWYG editor for Drupal 7.
It's a standalone module, unrelated to the existing, for a short while revived TinyMCE module, and also unrelated to the Wysiwyg module.
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Based on work done for the Backdrop CMS TinyMCE integration module.
From TinyMCE backport.
Add TinyMCE 6 support in the Wysiwyg → module.
Active
2.0
Editor - TinyMCE