CPI-PI vs CPI-DS with Development Perspective

Hello Experts,

Can somebody please let me know how big is the difference between CPI-PI and CPI-DS , i have already seen this thread which gives me idea about the difference between them during runtime how they behave.

In simple words what is understood is ( CPI-PI = PI on-premise and CPI-DS = BODS on premise)

But given an artifact to be designed in CPI-PI and CPI-DS how big is the difference in developing that artifact in these two? is knowing one help me to understand the other one ?

I have one tenant in which i see Data service at the right top bottom but i can see similar architecture like Manage, Design, Monitor etc etc..

Br,

Manoj