I have an app built with Glides which tracks monthly expenses. But i want to expand it, to have my banking information and track every inflow and outflow
If your bank has an API, you can possibly update the info to your Sheet using Integromat or Zapier.
You may want to have a peek at Glides Legal documentation before expanding your app.
Be careful not to use sensitive data in Glide in anyway. It could live in your GSheet just don’t connect it to Glide.