Actually over the couple of years, the db size has grown from few tens of GBs to such a huge size. At the time of design, we have kept the settings as 50 seconds for worst case scenario. We can't afford to increase this time now. And there are a lot of applications depending on the database doing high volume transactions that tlog size is also getting unmanageable..Please suggest a different backup solutions available.

By the way, you mean TLog can't be 100TB for this database ?