Staging site

Hi, we have multiple sites where we are using staging sites on WP Engine and Siteground which all work well for us pushing sites from staging to live.

However, we are looking for more of a complex staging site. We are going to have a website that will be both in staging and live. We will be developing new features in staging, but sometimes urgent content updates etc come in that we want to push live (and not the current developing we are doing). We are looking at GIT, and whilst this is a lot better for what we need, this seems to be good for pushing live certain files only.

For example a scenario could be we are updating all posts with a new design in development. Our client then has a text update on a post type post, which is say services. So I want to push live JUST the 1 service page, and leave the files, other posts/pages and other service pages as they are.

Would this plugin be able to achieve this? We basically want a complex server where we can just push specific posts/pages live. And say for example we are working on a CSS file, we only want to push live say lines 300-305 instead of the whole file.

Is this possible?

Thanks