There is no easy way to convert a Google Sheet table into a Glide table.
But… if your only reason for doing that is to minimise your row count, then you’re barking up the wrong tree 
Glide table rows count exactly the same as Google Sheet rows when it comes to row count limits.
In fact, if you’re concerned about row limits then you are better off with Google Sheet based tables, as it’s much easier to move rows out of a Google Sheet than a Glide table.