Actually both DP 203 and DP 700 exams are different exams focusing on different MSFT offerings pertaining to data engineering.
DP 203 focuses on Synapse whereas DP 700 focuses on Fabric both of which tools are used for data engineering.
So in case if your work technology is Synapse, would suggest to proceed with DP 203 irrespective of whether it is getting retired as that would help organizations understand that you are aware of synapse