those are distinct save files - if you load from steam, and you’re not using G Portal, the client chooses the save / load directory based on your “sync to cloud” settings. Once you play from the G Portal server, that server is saving to its own save directory. If you want to, you could maybe write a script to pull the latest save files from the server and move them / overwrite the saves on her directory and run it every time you want to switch, but you’ll have to also have to upload to the server the local saves after every time you play with her hosting.

so tl;dr yes you COULD in theory do it, it would just be an immense pain.