Okay, thanks - that helps to clarify.
When you import data from a Google Sheet in that way, Glide creates a separate copy of your data in native Glide Tables, which is in no way connected to your original Google Sheet. So the behaviour you see is correct and expected.
In order to have the data sync back to your Google Sheet, it would need to be connected as a data source. However, as you are on a Free Plan you do not have this option. You would need to ugrade to a paid plan.
Learn more below: