If a data change is initiated by the app, then that change will first sync to the database on the glide server, then that will initiate the sync of the data to the Google sheet. If there are calculations that happen in the Google sheet and they happen quickly enough, then I believe Glide will do another check for updated data in the Google sheet to update the glide database before going to sleep for a few minutes (assuming you have pro and have the background refresh/sync turned on). If you do not have background sync turned on, then the sync between glide and the Google sheet will only happen if data changes on the glide side, or Google initiates an update and sends it to glide. Once the glide database has been updated with the latest Google sheet data, then it will push it out to the local copy of any app that is currently open.
Glide can’t ping Google’s API every second to check for updates and Google isn’t going to push out updates every second. That would probably kill the internet, or drive costs above anything we could afford.
What you are experiencing is normal. The app itself does not have a direct connection to the Google sheet and most likely doesn’t know that a Google sheet even exists. It syncs with the glide server, and the glide server syncs with the Google sheet. It’s not reasonable for that much data to travel back and forth real time. It happens in batches with breaks in between, but glide will initiate a check for updated data if you made a data change on the glide side, or the auto refresh (which runs every few minutes) occured. Anything relying on Google to send the data to Glide is at the mercy of Google.