How certain are we that all of these items will not produce change runtime behavior when applied? I ask because the result of this operation is likely to be difficult/impossible to review.

Does this fix #43503 ?

❓ Before moving forward with this, can you confirm the following behavior:

1. Team configures a code style rule with severity hidden (or suggestion)
2. User enables the code fix for (1) as part of the code cleanup profile
3. User runs Code Cleanup on Solution
   For the above scenario, the Code Cleanup operation should take no action, as the project is not configured to enforce consistency for the item in question.

Need to understand this perspective a bit better. If the team does this:

Team configures a code style rule with severity hidden (or suggestion)

I interpret that as saying "this is style isn't required but if you think it makes sense then apply it".

An individual developer then does this

User enables the code fix for (1) as part of the code cleanup profile

Saying "even though this is optional I am opting in to this being done".

In this case not applying the code style when code cleanup is run would both

1. be inconsistent behavior with how code cleanup works today
2. would give the user no recourse for applying code style options on code cleanup other than to set them as warnings

How certain are we that all of these items will not produce change runtime behavior when applied? I ask because the result of this operation is likely to be difficult/impossible to review.

Don't know how relevant that is. All code fixes change semantics in some way. The assumption here is that the default code cleanup profile will not include all of these code style options but users can choose to add them if they want to. This mirrors the behavior we have had with dotnet format for nearly two years.