According to Kay Smith, German Aircraft of the Second World War the Ta 153 was similar to the Ta 152C (so Db 603 powered) with a new, long span, high aspect ratio wing.
One Ta 153 was completed - Fw 190 V32/U1. No mention whether it flew, or not.
I think the Ta 153 wing design was considered to be an improvement and was adopted for the Ta 152 - basically the Ta 152 was considered to offer most of the advantages of the Ta 153 while minimizing delays.
From the looks of it, it cannot be a "new" aircraft," but has to be an Fw 190 development. They used a DB engine and possibly new wings, but it was apparently an Fw 190 with a few modifications.
It would''ve been a "new" aircraft much in the same way the P-51 H was "new": Superficially similar but little parts commonality. Hence Ta 152 was the better option.