How to post using REST API to store unmodified content in a post?

I would like to store HTML content in a WordPress post by using the content field or using a custom field.

I would like to use the content field but in the past WordPress would modify the content. See here.

I noticed recently there may be a content_raw field but when I search online for more information I don’t see any mention of it. If that does not exist then I would save the html content in a custom field but I don’t know if that’s possible to do with the REST API.

My one requirement is that I cannot edit the PHP to remove filters.

Similar but not the same post:
Store unmodified text content in database