What you can do is use a microflow as a datasource for your templategrid. Then wrap an object around your template grid that holds an attribute what the sorting should be. When clicking the ‘High to Low’ button you should update the sorting attribute on the context object.
Then, after a button click, refresh your context object, which in turn refreshes template grid. The last things is sort the list in your microflow datasource according to the sorting you keep track of on your context object.
Let me know if this makes sense.