Actually the metatag module provide a type of field, that store information to the node the same as the other fields does. It just have different kind of representation in form and view displays.
I have pushed a new type of LLM and base field plugin for Automators AI, which allows setup an automation to content types which has fields of type Metatag. There are some todos that needs to be provided, and also currently only the title and description of the metadata are implemented. The issue needs more work.
Also, there are another approach out of the box which can be used here. The metatag module provides a field tokens, that can be referred to any type of metatag property. For example if you have a text field "Seo Title", the title tag can be set to use this field, and this field can be set to use Automator AI.
All clear now. Thank you for developing this module!