Help! Need some usability tips!

Hello fellow UXers,

I’m having some doubts regarding the navigation of the app I’m designing and was wondering what your thoughts were on this challenge. Here it goes:

On smaller devices the space between the top nav tab (balance/savings) and the bottom bar (fixed at bottom of screen) is quite small. So I was wondering if it would make sense to hide the top nav tab when scrolling down and make it appear when scrolling up (common pattern). If so, I would keep the top nav bar (with logo/profile) to keep some context and consistency on overall. Would that make sense?

This is the behavior that material design (which I’m using) suggests, however, don’t seem to find any clarity there: App bars: top - Material Design

All suggestions and feedback are welcome! Thanks in advance!

What if the Top bar is reversed , I mean fixed at bottom. Reason is that it will discard the space issue and toggling between balance and savings will be easy as it will be in a range of finger tap.