Will the database save data if still in process of filing taxes, but need to return at a later time? Login multiple times and not lose the progress I have made?

Yes, it saves between sessions.  That's very common behavior for million's of folks.

The only condition where it may not save absolutely everything, is if you are (say) in the middle of an entry on a specific form page, like halfway thru a W-2....and if you log out without working out to the end of that specific form entry, it may, or may not save what you've put in that form.

Another caution...do not go thru the actual filing & transmit step and expect to come back and change anything.   IF you hit the "Transmit" button...it's gone, and you cannot get it back to correct it until the IRS "Accepts" or "Rejects" it.  If they "Accept" it, then you are stuck waiting until March to go thru the messy Amendment process.  So take your time and get it right the first time.