We understand Inline comment facility is available only for the below case:
  1. In the block editor and
  2. Read Only option must be disabled in the workflow stage.
As per standard process, in the Review stage we mandatorily needs the inline comments facility to highlight the content for mentioning the specific details.
But the real documentation restriction issue starts here.
For enabling the inline comment we need to disable the read only mode and now reviewers can mistakenly or intentionally edit the documentation. Reviewers don't have right to edit the documentation.
Could you please enable inline comment facility for all the roles, even if the read only mode is enabled.
Apart from contributor all the stages required to provide comment For Example:
Grammar Review: Reviewers can only highlight and comment the required grammar and spelling correction needed to be completed.
Technical Review: Reviewers can only highlight and comment the required UI, GIF, Videos, Files, and content correction needed to be completed.
In short: Apart from contributor no one should have rights to edit the page, but they can provide inline comments.
This is the standard process all the documentation teams are following in all organization.